FAQs: All about fermented cod liver oil (and why I don’t take fish oil)

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A note from me before you delve into this extensive Q&A on fermented cod liver oil:

Fermented cod liver oil is the only “supplement” I take regularly and I recommend it for others as well. I first learned of this product several years ago while beginning my nutrition studies and while weighing the differences between it and a standard omega 3-rich fish oil supplement. I chose to move forward with FCLO and, based on my continued studying and research on the topic, will remain taking FCLO and not an isolated polyunsaturated fatty acid / omega 3-rich fish oil.

Additionally, when I dug into the research for this post, I ended up taking myself down a bit of a rabbit hole and discovered more resources than I thought would exist on the production of not only fermented cod liver oil and cod liver oil, but also fish oil. In my research I've discovered that the industry around and production of fish oil is enormous and is very much like that of seed oils. I'll do my best to delve more into these topics in a follow-up post to this one in the very near future, but I didn't want to delay sharing this one as wading through the rest of the information I've discovered will take me some time.

Please note: With this post, as with anything you read on this website – the information is not intended to be a replacement for professional medical advice, diagnosis, or treatment. Understand that tens of thousands of people read this blog, and I am not able to tell every unique reader a specific dose that is right for you, your family, or your friends. This is information for you to use to form your opinion and take action thereafter – or not. 


Chris Kresser, L.Ac

Chris Kresser, L.Ac


“Fermented cod liver oil is the one supplement I think nearly everyone can benefit from. I've seen it clear acne, lift depression, balance hormones, and reverse autoimmunity. I use it myself and recommend it to all of my patients.” – Chris Kresser, L.Ac.


What is fermented cod liver oil (FCLO)?

Fermented cod liver oil is a cold-processed form of oil that is gently made from cod livers. The fermentation process allows the oil to be separated from the livers without damaging the vitamin or polyunsaturated fatty acid (omega 3/EPA/DHA) content of the oil. This oil is then gently purified and then combined with flavorings (except in unflavored varieties) and bottled or placed into capsules.

There is currently only one company producing fermented cod liver oil that we know of, Green Pasture – many people find the cinnamon flavor most palatable. (Note: Balanced Bites is not affiliated with nor sponsored by Green Pasture in any way.)

How is FCLO different from standard cod liver oil or fish oil?

fcloVSfishoilSQProcessing is everything. Cold processing and fermentation protect the naturally occurring nutrients (omega 3 fatty acids as well as vitamins A & D) present in cod liver oil, however, heat processing will damage them.

In order to make use of nutrients that we eat in our foods, a reduction process needs to occur. We consume macronutrients (protein, carbohydrates, and fats) and micronutrients (vitamins, minerals, and phytochemicals), but the end usable form of these constituents are the metabolites of each: amino acids, glucose, and fatty acids and the individual molecules that make up the micronutrients.

In our bodies, digestive breakdown is the mechanism by which we do this internally – by means of not only the physical churning in our stomach, but also by means of stomach acid, bile, and, perhaps most notably digestive enzymes.

There are several ways in which the reduction of nutrients may occur: heat, synthetic chemical processing, and digestion (or fermentation, which is an exogenous means of pre-digesting nutrients).

Heat is damaging to delicate nutrients, especially when they are isolated from their whole-food source.

Synthetic chemical breakdown of nutrients is damaging as well. 

Digestion or fermentation (enzymatic breakdown) is by far the safest and most effective way to reduce the molecular structures in foods to their end usable constituents.  (If you are an organic chemistry-buff, perhaps you'll know a lot more about what the following information means than I do) When reduction is initiated by digestion (digestive enzymes) or fermentation, 100% of molecules break “to the right” – which is how our body uses them best. When the reduction is initiated by either heat or synthetic chemicals, 50% of the molecules break to the left (which may be toxic or unhealthful at the very least) and 50% to the right.

I will get into a lot more on the differences of the processing and production of fish oil, cod liver oil, and fermented cod liver oil in a post in the very near future as I noted in my introduction. This is a big topic and deserves its own post. 

For more information on this redox process, check out the source of the information I just provided above in the video below from Dave, owner of Green Pasture.

How is fermented cod liver oil different from an omega 3-rich fish oil in nutritional content?

The main goal or focus of supplementation with fish oil is to increase your omega 3 fatty acid intake whereas the main goal or focus with fermented cod liver oil is to increase your intake of fat soluble vitamins that are critical for immune health – including vitamins A, D, and K2 – in ratios that are appropriately balanced for ideal nutrient assimilation from this whole-food source.

While there is omega 3 (Eicosapentaenoic acid – EPA, and Docosahexaenoic acid – DHA) content to fermented cod liver oil, the amounts are not concentrated to supply high doses of these fatty acids.

Furthermore, the primary benefit of fermented cod liver oil is the concentrated presence of naturally occurring fat-soluble vitamins: A, D, E and K2 that are scarce in modern diets. There are omega-3 fatty acids in fermented cod liver oil (FCLO), however, the cold processing, fermentation, and concentrated food-form of this supplement make it a much safer and more health-promoting option than isolated PUFA available in traditional fish oil supplements on the market.

I consider fermented cod liver oil to be more of a concentrated superfood than an isolated nutrient supplement. Some of the many other nutrients found in fermented cod liver oil include: CoQ10 (also rich in heart tissue and some fish like sardines) and various quinones (known for anti-tumor, anti-microbacterial, and anti-cardiovascular disease properties). There are potentially thousands of other unspecified nutrients within this concentrated superfood.


“One gram per day of omega-3 fatty acids from fish oil reduces cardiovascular mortality in patients with chronic heart failure or who have recently had a heart attack. However, fish oil may increase cardiovascular and total mortality, especially when used for more than four years in combination with a standard modern diet.” – Chris Masterjohn


What is the omega 3 content of fermented cod liver oil?


Click to view larger.

The funny thing about a whole-food “supplement” is that it's not produced with the same type of exacting methods as other highly refined omega 3, isolated PUFA oils are, so determining an exact EPA/DHA content is not quite so simple. Furthermore, the value of fermented cod liver oil (FCLO) is not primarily its EPA/DHA content, though it contains whatever amount is naturally occurring, not concentrated/isolated. According to Dave Wetzel, owner of Green Pasture:

15% of FCLO will naturally be EPA
10% of FCLO will naturally be DHA

1 teaspoon of ~5000 mg of total oil in 1 tsp
1 tsp contains approx 500mg of DHA
1 tsp contains approx  750mg of EPA
1 tsp contains approx 1250mg TOTAL of EPA/DHA omega 3 (or 1.25 grams)

500mg of fermented cod liver oil per capsule
8-10 capsules = 1 tsp

Skate liver oil contains slightly more EPA/DHA per serving than fermented cod liver oil at 15-16% DHA, 12% EPA.

Information isn't labeled because the industry is touting claims of the EPA/DHA content in fish oils, which, after processing/industrializing, the product is void of many nutrients and all that remains are EPA/DHA – so that is what is marketed. Farmed fish can change the fatty acid profile of an oil.

photo credit: http://nourishingourchildren.wordpress.com/

photo credit: http://nourishingourchildren.wordpress.com/

Also according to Dave Wetzel, (the company who is the sole producer of fermented cod liver oil at this time),

“We do not have a deep focus on the fatty acids in the FCLO because, over time and work, I have concluded that these fatty acids are not what the focal point of the product should be. The only reason EPA/DHA/Omega 3s are discussed/pushed to the degree they are is after one completes the industrialization of these oils they have destroyed/damaged the real deal and they are left with some fatty acids. One always sells what they have. In the case of industrialized fish oils, fatty acids are about all that is left of value.

This is not to say that these fatty acids are not important. These types of oils will always contain a good supply of EPA/DHA and Omega 3s. The real story of Fermented Cod liver Oil is beyond this topic. I think the real story  is the thousands of other molecular structures known and unknown.

In our society the question of EPA/DHA and Omega 3s persist so here is how you can calculate this total for any product if you know the % of EPA/DHA/Omega 3 in any oil.”

That said, I am currently of the opinion that supplementing with an isolated omega 3 polyunsaturated fatty acid is not the best route to improving the omega 3 content of our cells. I have yet to come across a standard fish oil manufacturer who will discuss their production methods from fish to the consumer. What we know about delicate PUFAs is that they are highly oxidizable (susceptible to damage) by the actions of light, heat, and air. We also know that this damage occurs at a much higher rate when the PUFAs are isolated, meaning not within their original, whole-food form. For example, omega 3s in fatty cold water fish are not likely damaged by cooking methods such as poaching or baking, but when oil is extracted from the seed of the canola plant, the remaining delicate PUFA is likely already damaged by the processing it has undergone, and then we are told to cook with this oil. I believe this to be the larger issue around inflammatory PUFAs entering our system than a lack of healthful omega 3s.

Bottom line: When nutrients are readily available in food, we should eat them that way. If omega 3 fatty acids are your main goal of taking a fish oil or even fermented cod liver oil, increasing your fatty cold water fish intake is more likely your best bet.

What if I want to take more DHA than fermented cod liver oil provides?

You may be interested in trying a fermented skate liver oil which is a very rich source of DHA. Skate liver oil contains slightly more EPA/DHA per serving than fermented cod liver oil at 15-16% DHA, 12% EPA.

How much vitamin A and D are in fermented cod liver oil?

vitaminsADinFCLOUnfortunately, the levels in each batch of fermented cod liver oil vary with the batch itself as well as with the testing methods and labs use.

The best estimate that Green Pasture has is roughly 800 IUs of vitamin D per mL, though the company and a lab used to test the vitamin D content has stated that the hard and fast number-value of the vitamin D content may or may not be as indicative of its efficacy as the synergistic value of the vitamin D contained therein. The vitamin D, which is mainly D2 and some D3 in cod liver oil, is not added to the product. It is not standardized and it is not synthetic. It is present in the form of a variety of metabolites, not only one form as in most supplements. Historically, IUs weren't how people determined dosages, we merely used a bigger or a smaller spoon to take our cod liver oil.

In terms of vitamin A content, the vast majority of the content within fermented cod liver oil is in the form of palmitate and some retinol. Again, without it being an added ingredient, it's nearly impossible to provide value counts for isolated nutrients within the product for every batch made.

The amount of vitamins A & D in fermented cod liver oil is in a 10:1 ratio balance so that you will be consuming 10x as much vitamin A as vitamin D with each dose – these are natural, healthy, and appropriate levels as they occur in a whole food.


“When someone is looking for numbers, its almost like drug terminology. Cod liver oil isn't like that. We're not adding anything to the product.” – Dave Wetzel


“…we have continually pointed out that vitamins A and D work together and that without vitamin D, vitamin A can be ineffective or even toxic. We do not recommend Nordic Naturals regular cod liver oil or any brand of cod liver oil that is low in vitamin D. But it is completely inappropriate to conclude from this 2004 study that cod liver oil is toxic because of its vitamin A content. Similar reviews could be put together showing the benefits of vitamin A and cod liver oil in numerous studies, including the studies from the 1930s. Obviously the solution is to use the type of cod liver oil that people took in the 1930s, which did not have most of the vitamin D removed by modern processing techniques.” – Sally Fallon

What were traditional uses for/benefits of cod liver oil?


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Source: http://archpedi.jamanetwork.com/article.aspx?articleid=1173883

Cod liver oil has been known for decades as a potent immune system supporter as well as for improving heart function, glucose tolerance, vision, and lowering systemic inflammation.

According to Krispin Sullivan,

“Cod liver oil greatly improves heart function to prevent heart disease and to treat it even in advanced stages, after a heart attack and after heart surgery. Cod liver oil alters the linings of the arteries in such a way as to improve healing after damage. This is attributed to the omega-3 fatty acids but vitamin A, D and K all have important roles to play in facilitating mineral absorption, improving muscle function and supporting elasticity of the blood vessels. The inflammation-reducing prostaglandins made from EPA help mediate the inflammatory response in the arteries. In other studies the heart-protective effect was associated with changes in the muscle response to serotonin, increasing the heart's ability to “relax.” In a study with rats, treatment with cod liver oil actually caused artery-blocking atheromas to become smaller and blood vessel diameter to enlarge.55 Weston Price noted that heart attack deaths increased during periods when the vitamin A content of the diet was low. Cod liver oil can provide vitamin A on a continuous basis throughout the year.”


  • Cod liver oil contributes to bone health, preventing bone and muscle pain and joint pain.
  • Vitamin-rich cod liver oil has been shown to support the health of pregnant women by improving the fatty acid profile of their breast milk to optimize brain health in the infant.
  • Traditionally, infants were given cod liver oil to support immune health until Dr. Spock began to recommend vaccinations  in its place.
  • Vitamin A has long been shown to aid in vision health in diabetics and non-diabetics alike.
  • FCLO promotes proper absorption of calcium and magnesium, thereby helping to normalize blood pressure.
  • Inflammatory conditions like colitis and Crohn's have been shown to improve with the type of omega 3s in FCLO moreso than to medications often prescribed.
  • Taken orally or applied topically, fermented cod liver oil helps to improve the quality of skin, both on the face and for issues of rashes, diaper rash, wrinkles, and more.
  • The vitamin A in fermented cod liver oil has been shown to be protective against cancer.

source: http://www.westonaprice.org/cod-liver-oil/clo-number-one-superfood

How much fermented cod liver oil should I take?

howmuchFCLOAs recommended by Green Pasture: (Dosage is best discussed with your physician.)

Below are some general ranges you might consider:

Fermented Cod Liver Oil
Children age 3 months to 12 years: 1/8-1/2 tsp
Children over 12 years and adults: 1/2-1 tsp
Pregnant and nursing women: 1-2 tsp

Emulsified oils are made of only 80% cod liver oil, so the dosages are slightly higher.

Fermented Cod Liver Oil & Butter Blend – 2/3 FCLO and 1/3 HVBO
25 pounds or less: 8 drops orally a day
25 pounds: 1/4 tsp a day
35 pounds: 1/3 tsp a day
45 pounds: 1/2 tsp a day
55 pounds: 2/3 tsp a day
Children over 12 and adults: as noted on the bottle [my note, Green Pasture did not provide a dosage recommendation here]

Chris Kresser, L.Ac. recommends a dose of between 5 mL to 10 mL per day for women trying to get pregnant or who are already pregnant or breastfeeding, and a dose of 5 mL per day for men.

Chris Masterjohn states that “An excess of the omega-3 fatty acid EPA from fish and cod liver oil can cause a deficiency in arachidonic acid. For this reason, cod liver oil should be used in moderation and in combination with a diet rich in egg yolks and organ meats.” In other words: more is not better. A standard dose is sufficient for most people.

Should I take FCLO on an empty stomach or with a meal?

It shouldn't matter much in terms of digestive function whether you take it with a meal or away from a meal as it is a complete superfood, not an isolated supplement. That said, if you do experience any issues when taken away from food, take it after a meal – morning or evening doesn't matter – just whenever you will remember to take it is the best time to do it.

Is fermented cod liver oil safe for pregnant/nursing mothers, children, and infants?

Yes. Many of the concerns pregnant women have about vitamin A toxicity should be quelled by the fact that FCLO provides vitamin A (and other nutrients) in balance as they occur in the natural, whole food of cod liver. Food-based nutrients are not the same as synthetic, isolated nutrient supplements and often do not carry the same toxicity dangers.

What is a good brand of fermented cod liver oil to purchase?

fcloThe only brand I recommend at this time is Green Pasture.

If I am sensitive to fermented foods, should I take a non-fermented cod liver oil?

I don't recommend this approach at this time since I have not been able to verify that other ways of processing cod liver oil are safe to my own standards. If you are unable to take fermented cod liver oil due to a histamine or other allergen sensitivity, you may want to increase your intake of fatty cold water fish and fresh liver from pastured animals as well as your intake of vitamin K2-rich foods like grass-fed butter, hard cheeses made from grass-fed milk, and some pastured, clean-ingredient preserved meats like salamis.

Should I be taking FCLO or FCLO/Butter Oil Blend?

If you are looking for the additional value of vitamin K2, then the butter oil blend is likely your best choice. Fermented cod liver oil on its own may have some K2 value, but with the butter oil added, the K2 value is higher. You may also choose to take the FCLO liquid and add butter oil separately to your intake. Butter oil is not the same as eating grass-fed butter or ghee as it is much more concentrated, however, if you feel you eat a very large quantity of grass-fed butter, you may find that you want to only purchase the FCLO on its own. If you have a strong sensitivity or allergy to dairy, you may find you react to the butter oil, though this is far less common than you might imagine since the proteins in the butter are removed to create the butter oil.

Capsules or liquid, which is better to get?

The choices of capsules versus liquid or gel (if you are getting fermented cod liver oil/butter oil blend) depends on your own preferences. The liquid or gel allows for a greater volume of dose per container, so it is a more economical option than capsules. The liquid or gel also allows for a more customized dose size, since you can pour or scoop as much or as little as you like, whereas the capsules limit this a bit. If you find it difficult to digest capsules, the liquid or gel may be your best bet. If you find that it is completely impossible for you to take the liquid or gel, then capsules are a good option to get your dose in. Most parents report that the liquid is easy enough for their kids to take.

How does fermented cod liver oil taste? Is there a flavor that is better than others?

If you get a flavored variety, it tastes mostly like the flavor you selected with a slight background of fishiness. I think the cinnamon flavor is the best and covers up the fishy taste/smell most effectively. Many I know find other flavors palatable, but the cinnamon is my top pick. Standard fish oils are often deodorized and then flavored, making them much more palatable. If you are consuming the oil from the liver of a fish, it should have some hint of fishiness to it!

How can I make my daily dose of fermented cod liver oil easier to take?

Check out Sarah Pope's video below!


Should I take a fish oil supplement?

Fish oil is very different from fermented cod liver oil. I don’t generally recommend isolated fish oil supplementation for a few reasons.

Fish oil or any other isolated omega-3 fatty acid supplement is geared toward balancing the ratio of n3:n6 (n=omega) in your body. If you’re eating a Standard American Diet, that ratio is likely 1:10 to 1:20. From an ancestral and general health perspective, this ratio should be under 1:4, if possible.

Instead of supplementation, I recommend that you eat fish (a whole food) to get omega-3. Nutrients in food are much more bio-available than supplements. It’s also difficult to know and trust the source of your isolated omega-3 supplements.

Additionally, omega-3 is a polyunsaturated fatty acid (PUFA), and PUFAs are highly susceptible to damage (oxidation from heat, light, and air) if not handled carefully and appropriately. I don’t trust that the delicate polyunsaturated fats in most omega-3 supplements were not damaged in the processing and extraction of the oil. Consuming damaged isolated omega-3 supplements is likely far worse than consuming none at all, so I don’t recommend them.

You may have read about how seed oils are produced in my post about canola oil. In my research on how standard fish oils are produced, I discovered that a very similar process is used and I will cover this topic more in a future post. For now, please take a look at the processing steps and the compounds removed by them that have been summed up in the chart below.

This chart was created by a fish oil industry website to explain the processing – this is not sourced from any organization who wishes to demonize fish oil – it is simply matter-of-fact information about this oil's production.

Processing steps used to purify marine oils

Carbon Treatment Removal of dioxins, furans, and polyaromatic hydrocarbons (PAH). This can be performed on the starting crude oil if the oil is to be sold into the non-industrial market.
Oil Storage Insoluble impurities, trace moisture and some phospholipids will precipitate out in the tanks. The combination is known as “foots”.
Degumming Phospholipids, sugars, resins, proteinaceous compounds, trace metals and other materials.
Alkali Refining Free fatty acids, pigments, phospholipids, oil insoluble material, water soluble material, trace metals
Water Washing/Silica Treatment Soaps, oxidation products and trace metals
Drying Moisture
Adsorptive Bleaching & Carbon Treatment Pigments, oxidation products, trace metals, sulfur compounds, dioxins, furans, PAH and possibly some pcb's.
Winterization Higher melting triglycerides, waxes. Used to enhance the unsaturated triglycerides.
Deodorization Free fatty acids, mono-diglycerides, aldehydes, ketones, chlorinated hydrocarbons and pigment decomposition products. This is usually the finishing step and results in a bland tasting oil.
Vacuum Stripping or Thin Film, Molecular or Short Path Distillation Removal of chlorinated hydrocarbons, fatty acids, oxidation products, PCB and free cholesterol. Sometimes this step is used as a replacement for the deodorization step.

source: http://lipidlibrary.aocs.org/processing/marine/index.htm

When it comes to omega-3/omega-6 fatty acid balance, I always recommend reducing omega-6 intake drastically (as you will do when you eliminate vegetable oils, grains, and legumes) before adding any supplementation of omega-3 fatty acids like fish oil. If you’re concerned about systemic inflammation, you may even want to watch your food-based intake of omega- 6-rich items other than oils. Nuts high in omega-6 fatty acids include almonds, pecans, pine nuts, pistachios, and hazelnuts. For the average person, eating foods that contain omega 6 fatty acids naturally is not likely, in my estimation, contributing to excess inflammation the way isolated forms of these fatty acids may be – from seed oils and especially damaged/oxidized seed oils. This is the main problem with restaurant foods and especially fried foods – it's not the potatoes that make French fries unhealthful, it's the old, rancid vegetable/canola/corn/soybean oils that they are fried in that make them unhealthful, pro-inflammatory foods.

Chris Masterjohn, Ph. D.

Chris Masterjohn, Ph. D.

According to Chris Masterjohn in his article “Precious Yet Perilous“:

  • The requirement for essential fatty acids is lowest in healthy adults and highest in infants and growing children, pregnant and lactating women, bodybuilders, people recovering from injury, and people with chronic disease. Alcoholism, diabetes, insulin resistance, certain genetic variations, and strict vegetarianism may make someone more likely to become deficient. Additional liver, egg yolks, and cod liver oil can be used to correct deficiencies.

  • Essential fatty acids are vulnerable to a process called oxidation, which can cause cellular damage. Replacing traditional animal fats with polyunsaturated vegetable oils may increase the risk of heart disease, cancer and total mortality.

  • One gram per day of omega-3 fatty acids from fish oil reduces cardiovascular mortality in patients with chronic heart failure or who have recently had a heart attack. However, fish oil may increase cardiovascular and total mortality, especially when used for more than four years in combination with a standard modern diet.


More related FAQs…

What is beauty balm and should I use it?

Beauty balm is a product we refer to often that has been made by Green Pasture and is a blend of oils, including fermented cod liver oil, that is created for topical application. The balm contains a proprietary blend of: Shea Butter, X-FACTOR Gold High Vitamin Butter Oil, Blue Breeze Organic Coconut Oil, Blue Ice Fermented Cod Liver Oil, Cranberry Oil, Organic Orange Oil, Lavender Oil. I highly recommend this product for anyone dealing with very dry skin or simply to apply for nourishment. I have seen great benefits from this balm applied to my face (clearer skin) and hands (softer skin) regularly.

Moller's processing Fresh cod, steam processing, gentle refining to remove impurities, checked 8x along the way for oxidation and vitamin content (A & D), not added back. The Norwegian Health Authority recommends it be taken daily from as early as 4 weeks of age.


Sources & sites for more information:

Cod Liver Oil Basics & Recommendations (Weston A. Price Foundation – Sally Fallon & Mary Enig)
Separating fact from fiction on cod liver oil (Sally Fallon's letter on Chris Kresser's site)
Cod Liver Oil: Nature's Most Potent Superfood (Chris Kresser)
Talking Nutrient Synergy with Dr. Chris Masterjohn (Episode #69 of the Balanced Bites Podcast)
Cod Liver Oil: The Number One Superfood (Krispin Sullivan – Weston A. Price Foundation website)
Superfood: Cod Liver Oil – Butter Oil Blend! (Liz Wolfe, NTP's website)
Precious Yet Perilous (Chris Masterjohn)
Vitamin D, cod-liver oil, sunlight, and rickets: a historical perspective. (Pediatrics. 2003 Aug;112(2):e132-5.)
Update on Cod Liver Oil Manufacture (Weston A. Price – Dave Wetzel)
Cod Liver Oil Manufacturing (Weston A Price – Dave Wetzel)
Celebrating Dave Wetzel and fermented cod liver oil (Nourishing Our Children)
Processing of standard cod liver oil (Moller fish oil website)
Purchasing FCLO in the UK – Red 23

Comments 177

  1. I don’t personally don’t supplement with CLO, but I recommend it strongly to people who are pregnant or wishing to get pregnant.

    I don’t take fish oil as I find it as reductionism. I eat 8 ounces of WC Pacific Herring once every week, and have large amounts of liver all other days.

    I think the worst part about fish oil is probably the mercury and malondialdehyde contraindications.

    1. Wow. such a thorough post. Thanks Diane!
      Just wondering why it’s good for those who are pregnant or wishing to get pregnant. Thanks!

    1. Post

      It really shouldn’t be problematic since, as noted above, the dairy proteins are removed – but this has to be figured out on an individual basis.

  2. Thanks for the great post Diane!! I have not taken a “fish” supplement for years until I tried Green Pastures Cod Liver Oil/Butter Oil blend and have not had any issues like I once did while taking the standard “fish oil” capsules. My husband and I (me more) eat a lot of salmon and sardines(me). My husband is still taking a standard fish oil, which claims to be cold pressed. I can easily switch him over to the cod liver oil (capsule) but he doesn’t like to take what is “recommended” on the bottle. As I saw on Green Pastures website, which is label for 2 capsules per day. If he is only taking 1 capsule per day, is that sufficient or is it more waste since he is not getting the full benefits?

    1. Post

      It’s a very low does if he’s taking 1 capsule per day. 8-10 capsules = 1 tsp as I noted and I’d say 1/2 tsp would be a minimum I’d recommend to take per day– so that’s more like 4-5 capsules.

  3. I recently started taking Green Pastures Cod Liver Oil/Butter Oil blend in the morning on an empty stomach. Do you recommend taking it with a meal? I have noticed (although not every morning) a slight/very mild upset stomach feeling/mild nausea but I’m not sure if it’s related (or, quite frankly, if it’s in my head).


    BTW I love love love your podcast :)) and Practical Paleo should be at my doorstep TODAY!!

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  4. Oh, Diane. You write wonderful articles that are always so timely for the subject matter! What a wonderful resource to pass along to friends and family. You’re making lives better!

    1. I enjoyed the article but have a logistics question. I have a half completed bottle of Nordic Naturals Ultimate Omega that I’ve been using for the last month. Should I throw these away?
      I also take the Green Pastures FCLO & Butter oil blend.

  5. I started taking the FCLO butter blend about 2 weeks ago and have since been getting heartburn. I used to get it all the time (and took meds for it) 6+ months ago before starting paleo but not really since then, until now. Is this normal? Am I taking too much or maybe I should take it with food?

    1. Post

      How much are you taking? I haven’t heard of this happening before, but you may be overdoing it, or try taking it after a meal. Be sure there isn’t something else that’s changed in the same time frame that you are forgetting about…

      1. I have been taking the suggested serving of 1/2 tsp that the bottle says. I am going to try taking it with my meal and if that doesn’t help I’ll decrease the amount.

      2. Ok, I took the 1/2 tsp with my breakfast (2 boiled eggs and 1/2 avocado- my normal at work breakfast) and now have the heartburn. So… I guess I should lower the dose?

        1. This may be unrelated, but avocados give some people heartburn.
          Maybe you’re eating the wrong breakfast with it.

          1. Eggs can also aggravate heartburn as well depending on the person. The combination of both eggs and avocado with the FCLO may be too much at once. You can experiment by cutting out one thing at a time and see what knocks it out.

  6. I have a two yr old son. I have been giving him FCLO Blend for a lil more than a yr now. I have been giving 1/2 tsp of the blend (based on WAPF)im afraid I may have been giving him too much now.I probably should have been giving him closer to 1/4 to 1/3 a tsp seems right (based on the above recommendations..which conflict with WAPF..i dont know which recommedations I should go off of? PLEASE HELP.


    So how often do you think we should get a childs vitamin d level tested?? What vitamin d range should we shoot for a child??

    If he gets alot of sun during the summer months,should he even take FCLO during those months,or just like 1/4 of his normal dose…so hes still getting his a,d,k in balance??

    See with the fact that the vitamin d amount can vary so much from batch to batch…its hard to find a safe range of what dose to give a child..im afraid we would have to check our vitamin d status all the time(every month)since we wouldnt know if we got a bottle that had alot more vitamin d…than our last bottle(from only a month ago)

    1. Post

      FCLO/BO are not supplements, they are super foods -I would not stress or worry about the dosage on them. If your kid seems to be doing well with what you give him, good. If not, change it. I would not personally have my kid’s vitamin D levels checked unless I thought he was not healthy or would possibly develop autoimmunity if that was rampant in the family. I think a lot of us are way too worried about things because we can test and see numbers, but we lose the forest for the trees here — is the kid healthy, happy, active, looks vibrant? Yes? Good. No? Look for answers…

      Traditionally more FCLO was given in winter than summer- and it was a bigger spoon or a smaller spoon. It wasn’t measured and dosed like a medication, because it isn’t one — it’s a concentrated food. Just go with what seems to be working for you/him and you will be fine.

      1. Thanks but i guess im just more confused now. I mean it is a “supplement”,you even call it a supplement in your first paragraph of this article. Chris Kresser calls it a whole food supplement. Its treated as a supplement even,the bottle has supplement facts. Im confused about you not having a dose recommendation-chris kresser,chris masterjohn,dave wetzel,wapf all have dose recommedations(3 of 4 of those recommendations are mentioned in this article even) If its as easy as doing a small spoon or big spoon,why even have all those other dose recommendations(kresser,masterjohn,wetzel)all of which are all different dose recommendations..as that seems to confuse the matter..since they all arent clear on a proper dosage.

        I love your podcasts,I love your cookbook.Im just trying to get a clear on this matter. If you can make it clearer..it be much appreciated.

        1. Post

          I give their recommendations so you can see what is out there in terms of what folks recommend. I can’t tell you what is right for you specifically. Either follow the guidelines that someone is recommending, or follow your instincts based on what you’re reading and what feels right for you. The same way I don’t give portion size recommendations for people but provide some ideas of ways to figure it out for yourself with food, that’s what I’m doing here. That’s as clear as I can be. I’m sorry that folks want me to dictate how much of things to eat or take, but it just isn’t what I do for the public at-large. I can make 1:1 recommendations for clients, but I don’t make them for broad populations.

          1. Thanks..i guess ill just have to give him balanced bites of it 😉 Theres four..maybe more..recommended doses for this whole food supplement floating around on the web..so i have enough different routes to explore..thats for sure…what a deep rabbit hole this is indeed…thanks for digging

  7. Hi Diane. 🙂
    New fan and follower to paleo. Love your book it’s simply beautiful. And thoroughly enjoy the podcast. I started with the first and working my way through.

    Made a version of your cabbage apple sauté recipe (yum). Also did a version of your roast chicken. (YUM!) it was the first time I made a roast anything (decade long vegan til now).

    Quickie… You mention D2 and that surprised me. Thought animal D was D3 vs plant based D2?

    A recovering vegan,

    1. Post

      I thought so, too- and so did Dave Wetzel, but it seems that’s what showed up largely when tested. I am waiting for Dave to give this post a look-see and let me know if anything I’ve shared is not accurate, but I haven’t heard back yet. Check out the audio files on the Green Pasture FAQs page- that’s the source of the information in that section. I’ll link to the page in the post again if I didn’t already.

  8. Great post and definitely will be sharing.

    FCLO is a staple in our home, even my 10 year old loves it. People cringe when I talk about it and I am excited to share your post, it so thorough and well thought out.

    Thank you.

    1. Sandra I am going to start giving my 8 year old the capsules….but for the LIFE of me I haven’t found dosage information for kids and capsules ANYwhere on blue pasture or here. What dosage do you give your son? I hope you see this. 🙂 thanks!

  9. Great post! Also, Practical Paleo is my favorite book at the moment, and I’m recommending it to everyone I know!

    I spent tons of time just 2 weeks ago looking into the fish oil vs. FCLO issue because it was time to order more product. I ended up ordering FCLO/BO for myself, but I ordered Carlson’s Finest Fish Oil for my husband. I’ll try to sum this up quickly:

    We’re mid-30s, active, healthy-eating people; although I’m more strict Paleo than he is. The problem is, my cholesterol levels are perfect, and eating Paleo hasn’t altered my numbers at all, but his LDL has skyrocketed the past year (he had the fancy, extended LDL tests done, and he did have moderately elevated bad LDL levels). His HDL is not low, but not as high as I’d like to see it – despite the fact that he consumes good Paleo fats (not veggie oils). My husband has an active job, and he exercises outside of work too. He sleeps well, he’s as fit as a fiddle (has never been one pound overweight), and deals with stress amazingly well. He also had a hsCRP done, and has no signs of inflammation. I just don’t understand why he has high cholesterol, but our doctor says it’s purely genetic – there is nothing he can do about it, except take a statin.
    We decided not to go the statin route for now, and the doctor recommended we try 1800mg of Omega-3 fish oil to see if that brought his numbers down. In just 60 days, his LDL came down almost 50 points to a “safer” range, but his HDL stayed the same. I just don’t know what to think about this – The post says to take FCLO as a superfood/vitamin supplement, and not for it’s Omega-3 content, but the Omega-3s are what lowered his cholesterol substantially.

    I guess my question is: Do you think FCLO would be a valid replacement for my husband’s Omega-3 fish oil supplement? I’ve read all of Chris Kesser’s posts on cholesterol, but my hubby’s cholesterol was really, really high…and that scared the shit out of us. There just isn’t a good explanation for it (other than he’s genetically screwed) due to his lifestyle and diet.

    1. Post

      You can do what feels right for you and your husband. I wouldn’t personally ever take Carlson’s (mainly for reasons I’ll hash out in a follow-up post on production of cod liver oil when it is not cold processed/fermented), but you guys have to make that call for yourselves. I think learning a lot MORE about cholesterol- the truth, what the numbers mean, which numbers are valid, etc. would take you farther than simply getting supplements to move numbers around to please the doctor. Understanding what cholesterol is, what it does, and which numbers actually matter, in my opinion, is more valuable.

      I highly recommend a the podcast series between Chris Kresser and Chris Masterjohn on Revolution Health Radio is excellent as well as an interview of Dr. Thomas Dayspring with Jimmy Moore on the Ask the Low Carb Experts show. From what I’ve learned from both of these, unless his LDL is over 200, he is not likely showing signs of Familial Hypercholesterolemia OR hypothyroidism, both of which are known to contribute to excessively high LDL measures.

      1. Thanks, Diane!
        His LDL is not over 200, but it was close before he started the fish oil! The Dr. checked his thyroid, and it was normal. I’d like to get him to agree to being more Paleo strict, but he’s not into extremes. I’ve been grateful that he’s been so willing to cut out as much gluten & dairy as he has, so I don’t want to push him. He thinks I cook with too much meat, and asks for more chicken and less beef. I compromise by making him fish, but only make chicken about once a week. He’s still holding on to more “conventional” wisdom than I am! I spoon coconut oil into my coffee, and he just shakes his head.

        1. Twice in the last 4 years, my husband’s cholestrol was high……235 and 220. Each time he made dietary/lifestyle adjustments…….lots of green tea, oatmeal for breakfast, more exercise, meditation. Both times he got it down to 185 in about 3-6 months. I don’t do paleo yet, so I am not sure the rules about oatmeal and green tea and I am not sure why meditating helped. But I thought I would pass this along just in case as we are big on avoiding statin drugs. My husband has the genetic predisposition as well and is in his 50’s. Isn’t fiber a biggie in lowering cholestrol because it helps draw the cholestrol to it and eliminate it?

  10. Thank you for this great information. I am still a little unclear about how to get the highest amount of EPA. Robb Wolf recommends we get 5000 IUs of EPA and more daily, if we have autoimmunity issues. What safe and effective product can I get that from that you recommend? I have taken Nordic Naturals, and noticed a huge benefit when taking 5000 IUs daily. Not so much from the Jarrow brand, though I am told it was much more “clean” and processed in such a way that makes you absorb it better.

    1. I think Robb Wolf may have reconsidered the recommendations on EPA made in his book. I write this based on the Paleo Solutions podcast he and Greg Everett had with Dr. Harris (I think it was #79). (I’ve been catching up on the older ones.)

  11. I take Carlson Norwegian Cod Liver Oil capsules. Respectfully, I cannot afford a $45 bottle of FCLO. I would also prefer to see some scientific results on other major sources of cod liver oil (like Carlson). As is mentioned in this post, the research hasn’t been done, so it seems a bit one-sided. I apologize if this seems rude. It’s not my intention at all. I would just like to see some information that does in fact state that all other sources of cod liver oil are inferior or potentially harmful. If you can point me in the direction of such resources, I’d be grateful!

    1. Post

      I think everyone needs to make a choice for themselves about food, super-foods, supplements, etc. There are many people out there who decided to “quit Paleo” and went back to eating grain products. If they feel good with that choice for their own health, I am all for it.

      It’s not so uncommon that folks have trouble digesting fermented foods, but, in my experience, it’s more rare than not to have a histamine sensitivity.

      I also think some folks may have digestive issues that need to be addressed and are not being addressed, regardless of the FCLO. Low stomach acid or sluggish gall bladder issues can certainly contribute to a problem digesting this fatty “supplement”/superfood.

      Lastly, it looks like this family has opted for another route of holistic health treatment/support in homeopathy, so they’re not simply ditching the FCLO and not looking for other immune support elsewhere.

      It’s absolutely critical that each person/family decides what is best for them. If something makes you feel sick, then by all means don’t take it 😉

    1. Post
    2. I just googled

      rosita real foods-extra virgin cod liver oil

      and clicked on their website.

      It says their extra virgin raw cod liver oil will be going GLOBAL March 1!!

      hmmm it looks like green pastures “may” finally have some REAL competition.They basically had the marketed cornered,since they were the only one doing clo traditionally (the right way)

      Will have to see how it stacks up to GP FCLO.

      Diane I hope you research/write about this possible alternative.(rosita real foods-extra virgin cod liver oil)

    1. Post
  12. Very informative article Diane. Thank you! I’m curious, an earlier comment mentioned taking FCLO while pregnant and especially while trying to get pregnant. Why is that?

    1. Post
  13. Since the vitamin D in FCLO is D2, do we need to supplement daily with vitamin D3? Could you point me to some sources of information regarding this? We used to take daily D3 but stopped when starting to take daily FCLO, only using D3 as an extra immunity booster when sick. Thanks!

  14. Finally our fish oil questions answered! Thank you for all the information in this post. I’ve been rotating a fish oil and FCLO pill everyday for over a year now. If I ever miss a couple days in a row, my body DEFINITELY feels it and tells me something is wrong. Sometimes it’s a little sickness or a tweak in the gym. Looks like I gotta step up FCLO and forget about the fish oil altogether. Thanks again!

  15. Thanks for tackling this topic. Honestly, this summary makes me more hesitant to jump on the FCLO bandwagon than before which probably wasn’t your intention 🙂 But perhaps the next segment will make fish oils unappealing all around.

    Considering the price tag for this product, it seems wiser to spend the money on wild fish, liver, ferments and pastured butter and just eat that. Bonus: those foods are delicious and make a meal. We’re lucky that we have refrigeration and these whole foods available year-round and don’t have to rely on putrefied fish liver byproducts to hold us through until spring.

    1. Post

      I agree. I think if you are eating good amounts of wild fatty cold water fish, liver from pastured animals, and grass-fed dairy you shouldn’t need to add this to your diet. For some folks who are healing and digging themselves out of a bit of a micronutrient “hole” so to speak, this can be a powerful addition to their otherwise healthful diet.

  16. hi, just wondering why the recomendation for fclo/bo blend is lower than for the straight fclo since the butter oil blend has less fclo in it? I take the fclo liquid but have been giving my one year old 1/2 tsp of the blend.

    1. Post

      I have shared information of what is contained in the servings, I did not make serving size recommendations. I did, however, note where others have given their recommendations, so if those are not clear, I’d recommend asking the source as to why! Thanks! 🙂

  17. Great post Diane! Looks like you covered just about all the angles and covered them well. I’ve been taking about a teaspoon of FCLO every day for over three years now and have had no respiratory illness (colds or flu) for over three years now. I used to get three to five colds every year all my life and I’m 60 now. So this is nothing short of a miracle for me. About seven years ago when I first changed to a traditional food diet, I started taking the Green Pasture high vitamin CLO, about half a teaspoon a day. I still got one or two mild colds a year on that regimen. Not long after they came out with the FCLO I switched and I’m glad I did. I have to agree that moderation is probably important with FCLO. Too much could be a problem for long term health. Also, some people may have trouble with the amines like tyramine in FCLO (and in most fermented foods), so it may not work well for everyone. Thanks again for the great post! 🙂

  18. Thanks for the thorough post. Wondering if I can recommend this to my dad who takes cholesterol medication and blood thinners.

  19. Thanks for the informative article, Diane! I’m very curious as to your thoughts on the mercury/PCB/toxin levels in Green Pasture’s FCLO. I’m well aware of the benefits of taking it and it seems like a fantastic super food, but I’m very hesitant because of the potential for toxin exposure. I talked with Dave from Green Pasture and requested a copy of the tox report/lab analysis, but was told that they don’t release that information.

    Even if the FCLO only contains a small/trace amount of toxins, wouldn’t that still add up over time? I understand that cod don’t accumulate as many toxins as other species, but given the declining state of our oceans, can we ever really be sure we’re getting a pure product?

    Would love to know if you have any “insider knowledge” on the toxicity issue. Thanks for your time and for putting this article together! 🙂

    1. Post

      I don’t personally think about this too much since I consider the nutritional benefits to outweigh the possible downsides here. Note: we are constantly exposed to toxins in our environment, and I might even go so far as to say, like with many other things in nutrition: the poison is in the dose… meaning too much may very well be too much— but I also think it’s VERY important to know how well your own body detoxifies. If you have issues with detoxification pathways (liver detox), then this may be of more concern to you, whereas this isn’t something I’ve dealt with much personally or in my practice, so it’s not something I focus on much or worry about.

  20. Hey Diane, glad this info is out there in all it’s glory! I’m struggling to find the conversion between the liquid and the capsules with the liquid noted in ml and the caps in mg. Any idea how may caps equal half a tsp?

    1. Post
  21. I’m already taking this so I find it fascinating to read more about the benefits it is giving me! I personally have only tried cinnamon tingle, but…I LOVE the taste. I just put it on a spoon and then eat it? No fancy methods over here! maybe wash it down with coffee since I take it every morning, but that is it :). And this coming from a person who doesn’t like fish…at ALL!

  22. Thanks for this wonderful post…I’m going to give FCLO a try to see how I feel. My skin becomes excessively dry during winter here in Colorado and I feel so itchy. Reading the other articles makes me comfortable with my decision about FCLO…only hesitating point-the price! But, I’d rather spend the money on health giving products than pharmaceuticals. One thing that has stuck with me is how Vit. A and D work together in sync…and with the lower levels of D in FCLO, do you think going outside for extended periods (like gardening and/or hiking) during winter and even summer be beneficial while taking FCLO? Thanks~Lisa

    1. Post

      Vitamin D from sun exposure is always great, but what we get in the winter is going to be less potent than in warmer months depending on where you live. If you’re in SoCal, then you’re good to go… I wouldn’t worry that vitamin D you get from sun exposure would offset anything you’re taking in the FCLO negatively, you just may not want to take as much FCLO when you are getting more sun because you won’t really need as much and it’s more cost-effective to eat some vitamin A-rich liver with your sunshine than take the FCLO in that case.

  23. HI, do you have writings on krill oil? I just went to an integrated med doc today, and mentioned your book 🙂 Which I saw in the Progress, last fall. Looking to learn more 🙂 My brother went to Syraucse…

    1. I’m fairly confident that the production of krill oil is the same as, if not extremely similar to, that of fish oil – I don’t recommend consuming items that have been through that type of processing. I will post more on this later when I get time to review more information to share!

    1. Post
  24. I have no clue on how it’s made. It’s from Dr.Merola. never bought it before to be honest due to it being so exspensive. Just wanted to know your opinion on it?

    1. Post

      Right, I can’t form an opinion on it at all without that information. It’s my sense that others shouldn’t either. We should know how products are made before we decide to consume them or not, right?

  25. Hi Diane, Regarding the quote on top from Chris Kresser, I am trying to find where in Chris’s articles this comes from, but I cant find it. Could you tell us where this quote comes from?

    1. Post

      Actually, Chris is a friend of mine and I emailed him to ask if he wanted to give me a quote to use with his take on FCLO. So it’s from his mouth to your ears- not from a post.

  26. From text above: “If you are looking for the additional value of vitamin K2, then the butter oil blend is likely your best choice. Fermented cod liver oil on its own may have some K2 value, but with the butter oil added, the K2 value is higher.”
    However, Dave Wetzel’s website states (his Blog section):
    “The Quinone structure will be totally different in the fclo vs the butter oil. I suspect that the quinone, hormone, vitamin, fatty acid,steroid,enzyme comparative structures between the Butter Oil and the FCLO are complimentary just as Dr. Weston Price Discussed when he discovered the synergy between the two. The Total Quinone structure is very high in both the butter oil and the fclo. I suspect the FCLO will be higher in K2’s than Butter Oil based on my observations on how the products are provided in nature, collected, prepared, and discssions noted in the Merck Index. The Butter oil will be highest in other quinones. Typical Total Quinone content of the FCLO will range from 30-90 mg per ml (note the unit of measures when comparing products), and the High Vitamin Butter Oil will range from 20-30 mg per ml total Quinione.”

  27. Diane, one of my dear family members is in a difficult situation. She lives in a part of the world where she can’t get her hands on fresh fish, and can only get frozen fish (usually hake) once a week. She is trying to follow a paleo diet, and is eating canned fish like sardines, tuna and mackerel and is also supplementing with fish oil. She cannot afford to get the FCLO (and it would most probably be a real problem to get it to her), so I am not sure what to say after reading your post. I recommended the fish oil supplementation to her some months ago, because of not being able to eat fish as we are able to regularly in our region. But now I am sincerely worried about her.
    What would be the best thing for her to do? Would it be better for her to ditch the fish oil altogether? Is there anything else she can eat to get enough omega 3 fatty acids?
    Thank you very much for your help.

    1. Post

      I wouldn’t worry about it much- I just wouldn’t recommend she takes much of the fish oils, not more than around 2g/day. I don’t personally take it because I have access to these other options. That said, if I didn’t have access, I’m still not sure I’d take fish oil as a replacement – I may just work on getting my omega 6 intake down a lot more, and focus on grass-fed meats (which other countries tend to have more easily/cheaply than we do).

    2. I don’t recommend fish oil, so how she wants to proceed is up to her. I do recommend the canned wild fish as you recommend – I think that’s the ideal way to get omega 3s in any case.

  28. I’m dealing with Early Childhood Caries (toddler tooth decay) and it seems everyone who stopped their kid’s decay did so with Green Pasture’s FCLO and HVBO. Many of them seemed to exceed the recommended dosage as well. I am interested in helping my son and avoiding/postponing dental work for as long as possible, but without studies to back up its safety in kids I kind of feel like I’m experimenting with him, which makes me a little uncomfortable. Right now I’m giving him 1/8 tsp each per day to keep him under the Upper Level intake of vitamin A for his age.

    1. Do you have any references for ignoring the National Institutes of Health’s allowances?
    2. Regarding mercury, do you know how one teaspoon of FCLO may translate to actual fish? (Or do you have any idea how I may answer that question for myself?)
    3. Did you come across anything regarding rancid livers being involved in the process: per: http://nourishedandnurtured.blogspot.com/2013/01/why-we-stopped-taking-fermented-cod.html

    1. So sorry for the delayed reply- this post got an overwhelming number of comments and I couldn’t keep up!
      1. I do not
      2. I don’t know of a major concern of mercury in the supplement, but I would contact Green Pastures about it.
      3. I haven’t, but part of that concern, IMO, would be moot since fermentation is actually the livers “going off” in order to preserve some of the nutritional value. That’s the F in the FCLO- which makes it different from CLO that isn’t fermented (which I currently do not recommend).

  29. Have you seen Nordic Naturals Arctic-D Cod Liver Oil? They’ve added 1000 IU of vitamin d3 (cholecalciferol) so I was wondering if you would feel comfortable recommending this product in addition to Green Pasture’s. I’m also curious as to what you think of Metagenics OmegaGenics™ DHA 600 Concentrate product, which has a 10:1 ratio of DHA:EPA. I’ve been told by psychiatrists and nutritionists that that could be very helpful in mitigating depression symptoms like lack of energy, irritability/mood, etc. Thanks so much!

    1. Post

      I don’t recommend that. The added vitamin D isn’t what I would recommend ideally- ideally it is present naturally. I don’t recommend any isolated forms, so the Green Pastures is the only brand I currently recommend, as noted above.

  30. I am pregnant and trying to figure out what is better to take in my situation: Krill oil, FCLO or FCLO with butter oil? I already take prenatal vitamins but also need something that will give me and my baby the necessary Omega 3s/DHA/vit D. I would really appreciate some help. Thanks a lot.

    1. Post
      1. Very good article, thanks. Since I already take prenatal vitemins that have 5,000IU of vit A is it ok to take more? I read and heard that you can only take so much of vit A, because too much of it might cause some birth defects. That might be a myth though, Please correct me if I’m wrong.

        1. Also, what is the recommended amount of Omega 3 and EPA/DHA for pregnant women. Is just taking FCLO enough? Thanks for your help.

    2. this study showed a gigantic difference between krill oil and fish oil on LDL and HDL:

      On 1g of krill oil per day, HDL increased 43% and LDL decreased 32%. On 3g of fish oil, LDL decreased 4.5% and HDL increased 4.2%.

      For more Paleo Diet hacks: http://paleohacks.com/questions/383/confusion-between-fish-oil-krill-oil-cod-liver-oil-as-sources-for-omega-3-fatty#ixzz2SZ8toSeV

  31. I was extremely interested in the part you cite from Kessler about the role cod liver oil can play in helping heart function. A relative recently suffered a MAJOR heart attack (has had heart issues/attacks for many years), and I told him about FCLO but he seems to think that he can’t take it because of the presence of Vitamin K (apparently it’s blood clotting). That left me very confused because if vitamin k was such an issue, and I’d think that everyone with heart problems would then want to avoid it, then they wouldn’t recommend it after a heart attack or surgery. I know you’re not a doctor, but if there’s any information you can point me towards I’d greatly appreciate it because I don’t want him to miss out on something that can actually help his heart heal! But obviously if he really can’t take it I don’t want to push it. Thanks!

    1. Many heart attack/heart surgery patients are given wafarin/coumadin, which is an Rx blood thinner and are also recommended to avoid vitamin K and foods rich in it so as not to counter-act the effect of the drugs. In a normal functioning body, we want and need vitamin K (K1 and K2) for various purposes. I can’t make a call on whether or not this supplement is appropriate for your relative, however.

  32. Just got FCLO/Butter Oil Blend – Cinnamon Tingle flavor is NOT bad at all. Much easier to take than fish oil I used previously which was Carlson’s and Stronger Faster Healthier.

  33. This stuff is GOOOOOOOD only problem is you may want to eat the whole bottle in a couple sittings – the hardest thing I did was trying to only take 1 spoon a day – only had the cinnamon flavored one, and am certainly going to order more.

  34. Have any of you gotten your serum 25-OH vitamin D levels tested while on the FCLO? I took my 1 tsp/day of FCLO with butter oil for a year without any additional synthetic D3 supplement and my vit D level came up as deficient! I give 1/2 tsp/day of FCLO to my son with Thorne’s vit K2 (because of an anaphylactic dairy allergy, he can’t have the butter oil) and his vit D level was worse than mine!

    1. I wouldn’t really consider FCLO/BO as a solitary source of D3- you should really be getting it mostly from the sun, then some from the FCLO. There has also been new research around what levels of 25-OH D should measure at varying times of year and deficiency in the summer may not be the same as in the winter (meaning perhaps winter levels should naturally be lower and that’s okay). Have either of you been healthier/sicker than the other with these varying measured blood levels of D? Curious…

      1. Hi Diane,

        Thanks for the reply. We live in a part of the world that is quite cloudy, gray and rainy for about 10 months of the year, so we don’t get alot of sun. I actually thought that FCLO was supposed to be adequate as the solitary source of D since it was supposed to have so much D in it. I replaced my synthetic D3 supplement with the FCLO/BO, thinking that I was actually getting more D than with the supplement, based on the D estimates from Green Pastures. I was taking about 2000 IU of D3 supplement before I switched to using only FCLO/BO for my D.

        Do you have the reference for the new research?

        When my D level was found to be deficient, I was extremely ill with physically and mentally debilitating symptoms. I was no longer functional. Once I started supplementing with 5000 IU synthetic D3/day on top of the FCLO/BO, I started getting better, but I’m still not myself yet, even though my D levels are now about 50ng/ml. I think the low D levels triggered some autoimmune issues in me and I now have to deal with that.

        For my son, he doesn’t seem to be any sicker – thank goodness – so I’m hoping that I can just add D3 to his FCLO to bring his levels up too.

        1. The information I gathered recently I don’t think applies to those with autoimmunity, so there ya go… If you can find a safe tanning bed (search on mercola.com about that) I might recommend some very short exposure to that regularly for D3 as well as maybe adding a few potent drops of an emulsified D3. There are different approaches for different situations, so this is one I’d say to go for a bit more of the D3 on… info from Chris K on vitamin D is what I’ve been listening to- great stuff > http://chriskresser.com/surprising-new-vitamin-d-research-the-myth-of-multi-tasking-and-how-the-internet-is-rewiring-our-brains

  35. Hi Diane, Green Pasture’s website has been down for a week or so. Any idea what’s going on with them? Am hoping to order more butter blend cod liver oil.

        1. I don’t think it’s an issue since it’s in whole-food form. The only concern I might have is if you display any signs of iron overload (more so with the liver if you ate that much every week perhaps). I think that’s about 10-11oz…? If you feel good it sounds legit to me.

  36. Diane-

    I am on intravenous TPN & lipids, and trying to slowly come off as I gain more weight. My labwork is still showing a deficiency in Essential Fatty Acids, and I was just told by my hospital dietician to eat more margarine. (no other suggestions or advice, that was it). Please help! I came to your site as soon as I hung up the phone because I trust & highly value your insight. Would FCLO be an option to help increase this level? I wholeheartedly believe margarine cannot be my only solution! Thank you so much.

    1. Well, margarine is not anything I’d ever wish my worst enemy consumes – not that I have enemies. So I would absolutely never recommend you or anyone else consumes it.

      That aside, yes, FCLO is likely a good choices – but it’s also possible your gallbladder isn’t functioning up-to-snuff here. Often EFA deficiencies are a compound issue of not only a possible lack in dietary intake, but a lack of actual absorption once we eat them. We need bile from our gallbladder to emulsify the fats so we can absorb them. If you aren’t sure about this, it’s possible to ask about getting some oxbile/bile salts supplementation in as well.

      I’m not sure why you’re on the TPN & lipids as you haven’t noted that here, but there may be cause for some digestive aid supplementation to help once you’re eating more real, whole foods. Check out the digestion section of my book, “Practical Paleo,” for a lot more information as well.


      1. Thank you for your reply!! You are spot on, gallbladder has been removed. So supplementing with the bile salts makes so much sense. I have been on TPN since birth (now 28) for motility issues. Have received better advice from your book and site and the paleo community in whole than I have from any hospital or nutrition program I have been a part of, thank you so much for what you do. Helps those who are told to just eat more margarine live a better healthier life 🙂


        1. My pleasure, Jana – glad you found us all! It’s almost shocking, isn’t it, that the medical community has no connection with real food or using food/real support of normal body functions to help people? It’s sad and quite frustrating for you I’m sure- but there’s always hope if you seek the answers, as you are!!

          Keep me posted!

  37. I read this after hearing Chris Kresser mention on a podcast that this is the only supplement his daughter takes regularly. Green Pastures just got a new customer!

  38. Hi, I’m thinking of buying some fermented cod liver oil, but what I cannot understand is why shouldn’t I just buy Vitamin A, D and K2 pills that are so much more inexpensive, Is there a significant difference, and why?

    1. Anytime you can get something from food, you should. It’s likely that the other isolated nutrient supplements are synthetic or, in isolation, may not be as “perfectly balanced” as nature intended. It’s my opinion that food forms of nutrients are always superior to others – but certainly do what resonates best with your instincts.

  39. Hi,

    Do you by any chance have information on the totox value (peroxide and anisidine) on Blue Ice Fermented Cod Liver Oil? I find this very essential in determining the freshness of fish oils and cod liver oils.

    1. I definitely don’t have that info, but I strongly recommend contacting Dave Wetzel via the Green Pasture website as I know he loves to answer customer questions!

  40. Hi, I’m hoping you can clarify something for me please. I just received my butter oil/FCLO blend and in checking this site for dosage recommendations, I noticed that you have 55 pounds: 2/3 tsp a day and Children over 12 and adults: as noted on the bottle. Well, my bottle says the serving suggestion is 1/2 tspn which is LESS than the amount suggested for 55 lbs. I’d think that the dosage for adults would be the highest, or perhaps because kids are in development that age group needs more? Thanks!

    1. Thanks for bringing this to my attention. I would recommend 1 tsp/day for an adult. I will see about editing this as I thought that was what the bottle noted. Perhaps it did before and has changed…

  41. I understand that Carlson could be as good as Green Pasture, especially as it can be purchased for about half the price…

    1. I don’t recommend Carlson at this time. It is not a cold fermented product. Heat processing applied to isolated PUFAs is not going to produce the same result.

  42. The amount of vitamins A & D in fermented cod liver oil is NOT a 10:1 ratio. According to their test data page, it varies from less than 1:1 to around 5:1.

  43. regarding Omega 6s, what are your thoughts on taking supplemental GLA (from borage seed oil) or Evening Primrose oil?

  44. Hi Diane! Amazing article. I’m from Canada and it is really difficult to get the Green Pastures butter oil and fermented CLO blend. However, some health food stores sell them seperately. Would it make sense to take both seperately or are the health benefits only when they are blended?

    1. Whichever works for you is fine. I use a lot of grass-fed ghee in my cooking so I often just take the FCLO without the BO blended in. It’s a personal choice really — and not everyone tolerates the BO well so it’s nice to have options.

  45. I’d like to get the FCLO and butter blend, but I am concerned about it being shipped in this summer heat, do they ship overnight or pack in ice or anything to help protect the delicate fats?

  46. So I have your Practical Paleo book and I was going to buy the cinnamon gel FCLO as rec’d by your book, but when I went to Amazon to buy it, it’s $70!!!! That is crazy. No way I can afford that. 🙁 Even the other non-cinnamon gel versions are very expensive.

    1. You can opt to eat liver from pastured animals and wild-caught fish instead. This supplement isn’t cheap, but you get what you pay for. Cheap fish oil supplements… well, there’s a reason why they are cheap… ya know?

    2. You can opt to eat liver from pastured animals and wild-caught fish instead. This supplement isn’t cheap, but you get what you pay for. Cheap fish oil supplements… well, there’s a reason why they are cheap… ya know?

  47. Hi Diane, we’ve just started selling the Green Pastures range in the UK and Europe (www.evolutionorganics.co.uk). I’m taking the FCLO caps and butter oil separately. Reason being is that my daughter has problems with her teeth, and the butter oil is meant to be good. It’s not the tastiest on it’s own, so you need to be a little inventive with little ones! Any suggestions welcome!

  48. I think it is important to mention when you recommend any supplement that it can be incredibly toxic to some people, particularly those with compromised health. The FCLO definitely falls into that category. When I became horribly ill a couple of months into taking it I suffered for quite a while before I figured out the cause and have since found qute a few people who had similar experiences. What happened to many of us is that the effects took a few weeks to start and came on very gradually, so we did not at first attribute it to the oil. While cod livers may indeed be a super food, it is not readily available in the amounts we are suggested to ingest by yourself and particularly WAP, and there are many conditions that are exasperated by the fermentation. I love your book and your website and it has helped me tremendously, but am always disturbed to see this so readily recommended without any caveats and warnings, and without any suggested substitutions. I now take MCT oil and while I do get great benefits from it I always wonder how it compairs to the FCLO, but can never find a comparison.

    1. Any food or supplement can be toxic to a person for sure. My biggest recommendation here is actually against “fish oil” and to eat whole-food forms of omega 3, but this post is to clarify FAQs I get about FCLO daily.

      MCT oil has none of the micronutrients that FCLO has – it’s primarily lauric acid, a great fat that has some fat-burning properties to it, but in terms of vitamin or EFA density, it’s fairly “empty” in that regard.

      Thanks for the comment, and I apologize for the delayed response.

    2. Any food or supplement can be toxic to a person for sure. My biggest recommendation here is actually against “fish oil” and to eat whole-food forms of omega 3, but this post is to clarify FAQs I get about FCLO daily.

      MCT oil has none of the micronutrients that FCLO has – it’s primarily lauric acid, a great fat that has some fat-burning properties to it, but in terms of vitamin or EFA density, it’s fairly “empty” in that regard.

      Thanks for the comment, and I apologize for the delayed response.

  49. Anyone experienced hair loss with FCLO? I am taking the Green Pastures one month ago and my hair is falling a lot. Same happened when I was on fish oil pills … please, I need help, I am taking it 5ml (1 tsp), I decreased it but my skin get worse so I am taking the tsp again,
    Thank you so much!!!!!

    1. I haven’t heard of this before, but it is always possible to respond negatively to new foods or new supplements. If it doesn’t work for you, then don’t take it. I would move to whole-food sources of the nutrients only versus the concentrated dose and see how you do (liver and fish).

  50. Dear Diane,
    Thank you for your meticulously researched article!
    A small question: If a person is eating organ meat (chicken or beef liver) regularly (4 oz. once or twice a week), should she still take FCLO? Is there a danger of toxicity if frequent organ meat consumption is combined with daily doses of FCLO?
    Thank you so much for your response, and happy New Year!

    1. I don’t think that the FCLO is necessary if you are eating liver and seafood regularly. That said, I also don’t presume toxicity is an issue since these are all whole-food sources of nutrients and there is a balance of vitamin D with the vitamin A you get therein. Food is always first, it’s just that many folks don’t consume much liver or omega 3-rich fish in a modern world.

  51. I’m really confused as to why there is more vitamin D2 than D3 in the GP FCLO, since D2 comes from plant sources. It seems totally counter-intuitive to COD LIVER oil. I’ve searched and searched and cannot come up with an explanation. Anyone?

    1. Perhaps ask Dave Wetzel of Green Pasture. If it was in the butter oil blend I might guess from the grass eaten by the cows…

      1. Thanks for the fast reply. I did send Dave a message shortly after posting here, and will definitely post the reply if / when I receive one.

        One thing I wanted to ask – I know you mentioned before that the FCLO should not be a solitude source of D3. Do you have any recommendation on a D3 supplement to go along with the FCLO, then? (Especially during the winter months where sun is at a premium.) I have been taking the Garden of Life “Raw” D3 mainly because I want to avoid the synthetic stuff, but ideally I’d like to take no supplements at all … just real “foods” like the FCLO. Thank you.

        1. I don’t. Sunshine and possibly eggs -both from poultry and from fish (roe) if you can tolerate them. I think those are the only other dietary sources… I recommend sun the most.

          1. Sunshine is definitely the ideal source, but during the winter months it can be tough. For argument’s sake – if you’re not getting much sun during the winter, would you then supplement with a D3? Or is the FCLO and eggs still enough?

          2. I’d say some low-exposure tanning in a bed/booth that has UVB rays with some UVA will be a better idea. But research that before you do it. The types of vitamin D we make from the sun exposure probably can’t be measured in only D3 form — so I’d opt for some tanning instead.

      2. Received a reply from Dave. (Wow – both of you are really on the ball today.)

        Here it is:

        “ocean is filled with both D2 and D3. see blog posting that shows first
        study on D in the sea, zoo and phytoplankton are loaded in both D2 and
        D3. we do not alter this nor add D3 as the other clo products… it is
        as it is… no one understands the pathway of D in fish. this study is
        barely moving at this point so the questions on this are not ready to be

  52. Green Pastures is all a marketing scheme. There aren’t enough EPA and DHA in the cod liver oil to make it worthwhile. Other products contain much more of it.

    1. You’ve missed the point of the article. I don’t recommend it for the omega 3 content primarily, but rather for the fat soluble vitamins. If you want omega 3s in your diet, it’s best to eat fatty cold water fish.

      1. You’ve missed the point of my post. You can get the fat soluble vitamins from other sources that have more omega 3’s. Green Pasture is pure marketing BS

        1. The point of this comment was to tell me that I can get FSVs from other sources of food that also have more omega 3s than FCLO?

          “Green Pastures is all a marketing scheme. There aren’t enough EPA and DHA in the cod liver oil to make it worthwhile. Other products contain much more of it.”

          I’m not sure how I missed your point. I don’t think that point was at all evident in that comment. If you would like to share information on other sources you think are superior, please feel free to list them.

          1. If you read between the lines I think my post was very evident. I’ll say it more clearly, this time: You’re wasting your money on Green Pasture products. You’ve been tricked by clever marketing on their part to believe their product line is better than it really is. There are superior products that offer the same fat soluble vitamins plus more EPA and DHA per serving, which is what you should be after as a consumer. Buying Green Pasture products is akin to flushing your money down the proverbial toilet.

          2. I don’t care to read between lines, Virginia, but if I did, there is still nothing you’ve alluded to that you think is a better product. Please share the superior products you recommend with anyone who might read this. I invite you to do so.

    2. if y ou want more than the supplied EFAs, take skateliver oil. AND take tbe FCLO and butteroil for the reasons she stated, Vit A, D and K.
      Not hard to follow.

  53. Thanks for all the great info, I just bought this Blue Ice brand (non-flavored) and am starting it today. I have a question that may sound dumb but can’t find it anywhere online…..do I continue to take a prenatal vitamin with this?(I am nursing) How about things like airborn/emergenC when I feel a cold coming on? Thank you!

  54. Excellent article. I am a Registered Nurse and have been taking the Green Pastures cinnamon FCLO and butter oil since October. I have been diagnosed with stage III endometriosis and menorrhagia and underwent a laparoscopy in May for extreme pain and a golf ball size endometrioma on my ovary. I tried every natural remedy, diet manipulation, and supplements but nothing helped the pain. The surgery helped lessen the pain overall, but I still had days every single month where the pain was debilitating, and I refused to be on continuous birth control, which is the conventional treatment for endo. I attended a reproductive endocrinology conference last year and heard a presentation about the link between endometriosis and lack of ability to absorb and process vitamin A, especially retinoic acid. In doing my own research, I found the FCLO was one of the best sources of vitamin A and read some anecdotal evidence of it helping other women with endometriosis. I can happily say since December I have had no endo pain and my periods are becoming shorter and more normal. Is FCLO a magic bullet for every condition? No, but disease arises from deficiencies, and in my case, the FLCO contains exactly what my body has been lacking. It has improved my quality of life immensely.

  55. I have been taking blue ice fermented skate liver oil 3 tablets and X factor butter oil 3 capsules.
    My tongue is very dry. I need to dring a lot of water.
    Is this normal. Am I detoxifying
    Kindly reply

  56. Hello and thank you for this interesting article. I have a question I cannot find answer to. I was interested to use this product for my immune diseases, but at the moment I have a lot of Candida. Knowing the destroying effects of candida on the gut, I think it’s a priority for me to treat it changing alimentation and getting some specific supplements. On Candida it’s better to avoid fermented foods (e.g. vinegar) but others are good because they bring inside some yeasts that are Candida antagonists. But what about fermented cod oil? I don’t know about the fermentation process in this case and what type of yeasts they use. Thank you and have good days :-), Giusi

    1. I’m not sure about this, but I think you could ask Green Pasture about the specific type of fermentation and any byproducts to which you may react.

  57. I recently found out that I am sensitive to Cod fish. I assume the FCLO is made from Cod fish liver, am I correct? Any suggestions for someone who cannot take this wonderful product? Thank you.

  58. I have been following Weston Price and taking the very expensive fermented cod liver oil for well over a year now. My vitamin D levels are pitiful (40). I also eat liver, grass fed beef, butter, caviar, salmon, seafood, etc. My doctor now has me on 5,000 IU of bio-available vitamin D, after suffering renal exhaustion, Vitamin C and Super B complex. I feel so much better.

    I am really upset that I took this during pregnancy and didn’t supplement more vitamin D for my baby and for me. I don’t think it is bad to take, I think it is good, but I CAN’T BELIEVE I am paying $60 a month just to have low vitamin D levels.

    I’m also glad I didn’t listen about the vaccines – as babies are dying here of whooping cough.

  59. I have a 3 year old picky girl. I got the chocolate flavor hoping it would be easy to take but its so strong, I dont know how i Could get her to take this. can you help me pls? I tried a chocolate smoothie but it defeats the purpose of healing her little cavity if its has sugar. :/

  60. I have found the use of the FCLO to be effective after 2 doses(using caplets). I have swelling in the back of 1 eye and after taking the FCLO, it has been greatly reduced and found my vision to be getting better day by day. I am going to continue to take this as I am sure this will be of great benefit.

  61. Hi Diane,

    I did not see that part of discussion on “why I don’t take fish oil”? Did I miss it? I would really like to know why you don’t take FCLO. thanks

  62. I know I’m late to the game with this post, but I just came across it. I was wondering what you think of Fermented Skate Liver Oil? I’ve had a hard time finding info about it. I’m also breastfeeding and pregnant so I was wondering if Skate should be a concern.

  63. Yes, few of my cousins have been taking fermented cod liver oil but after having such a bad experience, they stopped taking it. After taking fermented cod liver oil, they started feeling heartburn with some other gastrointestinal disorders such as nausea, gas, bloating and stomachache, even some of them experienced diarrhea.

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