Top 10 Reasons Fermented Cod Liver Oil is Rancid

Is fermented cod liver oil rancid? That’s the big question on everyone’s mind. It’s been the question plaguing me for months. What I’ve been saying from the beginning is I just don’t see how it’s NOT rancid…

Top 10 Reasons Fermented Cod Liver Oil is Rancid

Is fermented cod liver oil rancid? That’s the big question on everyone’s mind. It’s been the question plaguing me for months. What I’ve been saying from the beginning is I just don’t see how it’s NOT rancid…


Ever since Dr. Kaayla Daniel’s whistleblower report on Fermented Cod Liver Oil came out almost 3 months ago, there have been a number of rebuttals and responses that defend the FCLO. Lots of five-dollar words and sciency mumbo jumbo.

WAPF scientist, Chris Masterjohn’s high wire act in obfuscation is a prime example. TBA and TBARS and TOTOX, oh my!

I don’t know about you but I don’t even remember high school chemistry. So we’re gonna skip all that and cut to the chase — common sense. I wanted to write a very simple, easy-to-understand post that outlines some very basic reasons the FCLO has to be rancid. You do not need a PhD in lipid science to understand this stuff, people. It’s right under our noses, as you will see…

Unless Green Pasture Products can address all of the following points below, I find it very hard to believe that the FCLO is not rancid. Unless of course, it’s magic.

Facts About Fish Oils

Before we get started, let’s cover the basics. There are two fundamental things you need to know before you read this post:

1. Fish oils contain a high content of PUFAs (polyunsaturated fatty acids).
2. PUFAs go rancid, or oxidize, when exposed to heat, light and/or air.

Coconut oil, palm oil, and tallow are examples of highly saturated fats that can withstand more exposure to heat, light and air. That’s why you can store a bucket of coconut oil in the cupboard for months on end and why you can deep fry with tallow. Fish oils are much more fragile and go rancid very quickly and easily. They must be handed with great care in the manufacturing process and should be properly stored by the consumer.

Fish oil, unlike many other oils, has a chemical structure that makes it highly susceptible to spoiling or oxidation. The oxidation process begins as soon as the fish is caught and continues as the oil is exposed to oxygen, heat or light. (Source: Omega 3 Innovations Website)

Top 10 Reasons FCLO is Rancid

1. Exposure to Heat?

David Wetzel of Green Pasture Products has been very evasive about his production methods. We know almost nothing about how the cod (or pollock) livers are shipped from wherever they come from to Nebraska. We know almost nothing about his retrofitted “greenhouse” in Nebraska where he manufacturers the FCLO. There is no information available that I have been able to find about whether or not the greenhouse is climate-controlled.

In fact, it is not clear whether or not he does manufacture the FCLO in the “greenhouse”… according to a statement on GPP’s website from ABS Corporation, they not only package all the Green Pasture products but they also manufacture the products:

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So I guess we need to get information about whether or not the FCLO is exposed to heat not only from Dave but also from ABS Corporation. I have not called or emailed them yet to request an interview but I think that should be next on my agenda.

Needless to say, lots of questions. No information is available to ensure that the ingredients and products are not exposed to heat throughout the shipping and manufacturing process.


2. Exposure to Light?

There has also been confusion about whether or not Wetzel exposes the oil to light. Most (if not all other) cod liver oil manufacturers keep their production plant very dark with low lighting to prevent exposure to bright light.

“Solar Activation” or Exposure to Sunlight

Prior to Kaayla Daniel’s whistleblower report, the Green Pasture FAQ page said that they exposed their cod liver oil to sunlight.


Do you solar activate your oils as Dr. Price did early in the 20th century?

We solar activate all our products as Dr Weston A Price did. Solar activation is simply exposing the product to the sun. Our Plant is a solar plant and we ensure that all our oils are exposed the the sun, moon and stars.

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Source: Green Pasture Products FAQ Page from August 9, 2015 (viewable via the Wayback Machine, or

Some time after the report was published (published on Aug. 23, 2015), the Green Pasture FAQ page was changed to say that they do NOT expose their oil to sunlight.

Do you solar activate your oils as Dr. Price did early in the 20th century?

Our plant is exposed the sun but this does not equate to solar activation as Dr. Price discusses. Dr. Price had a specific protocol and definition for the term solar activation and it does not occur unless uv rays are directly exposed to the products. In our plant the products are not exposed to solar uv.

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Source: Green Pasture Products FAQ Page Today

I find this very suspicious. Why change the FAQ? Is the oil exposed to sunlight or not? As Dr. Rudi explains in the video interview, (paraphrase) “if the oil is exposed to sunlight, it is definitely rancid”.

We need David Wetzel to shed some light (pardon the pun) on this and show us how his oil is produced. Is the oil exposed to the “sun, moon and stars” as he has said on his website for nearly a decade, or is it not?


3. Exposure to Air?

We do not know how the fish livers are transported to Nebraska. Are they protected from exposure to air during transport? We don’t even know what kind of fish livers they are (FCLO label says cod, DNA test said pollock) or where they come from…

We were led to believe the livers came from Arctic regions but now, according to Kaayla’s report, it looks like they come from Alaska, which makes sense since Wetzel’s old company was named Bering Sea, LLC.

Here’s the old label:


It’s hard to see but if you look very closely, it says the company is based in Seldovia, Alaska.

Green Pasture Products, Inc. is the name listed on the website… but owners David and Barbara Wetzel founded another company called Bering Sea, LLC in 2006. That company was then transferred to Blue Fish, LLC in 2007.

Why the name change?


The label was also changed to reflect the “Nordic” theme with talk about “Arctic cod” and flavors like “Oslo Orange”:


The new label also shows that the company is based in Nebraska. It says nothing about Alaska. Why? Was this an attempt to disguise the fact that Green Pasture Products used fish from Alaska? (Also, another sidebar, but notice that the new label says you should store it in the fridge… remember that when we get down to # 6 below…)

Sorry, I’m supposed to be talking about exposure to light here… but I think what you’ll find if you start trying to research David Wetzel and Green Pasture Products is there are lots of strange rabbit holes you find yourself going down… from changes to labels and FAQs and company names. Again… lots of questions…

The point is, we have no idea where the fish livers come from, how they are transported, and whether or not they are protected from exposure to oxygen during this process from the boat to Nebraska where the oil is manufactured.

We don’t know if the “10,000 gallon fermentation vats” Wetzel allegedly uses in his “greenhouse” are air-tight. We do not know if Wetzel uses nitrogen or argon gas to protect the livers or the oil in the vats.

And we don’t know at which point and how the livers are transported to ABS Corporation for further “manufacturing” and packaging. How are they protected from oxygen there? Is nitrogen added to the bottles during packaging?

Oh and I should add one more thing… competitor cod liver oil companies report that they process the fish within hours of catching and manufacture within days. Check out the Nordic Naturals and Rosita’s FAQs.

In fact, Rosita says in their literature that their cod liver oil goes from “fish to bottle within 48 hours”.


Here’s a video from Nordic Naturals showing how they catch the fish and and manufacture the oil. I highly recommend watching this video to understand how the cod liver oil is made (if you’re in a hurry, skip to 6:00 in the video).

4. Six Months in a Vat?

PUFAs oxidize over time. This is really my biggest question… how can a PUFA sit in a vat for 6 months and not oxidize? All of the above (#1-3) factors would need to be accounted for. And we just don’t have enough information on the manufacturing process of GPP. What we do know is sketchy at best.

Wetzel says he is doing things the “traditional way”… According to Dave Wetzel on the WAPF website:

South Sea Islanders put great store in shark liver oil—enduring considerable danger to procure the sharks even though other, less dangerous-to-catch seafood was plentiful. To prepare the oil, they put the livers inside the leathery stomachs of the shark and hung them in the trees for several months. As it ferments, the oil gradually comes out of the livers and fills the hanging stomachs! (Source: Weston A. Price Foundation website)

Here’s the key difference between shark liver oil and cod liver oil. Shark livers are naturally rich in antioxidants like vitamin E and squalene (Source). So perhaps the reason the South Sea Islanders could store shark livers for months outdoors is due to the natural antioxidants.

Cod liver oil does not contain antioxidants. So we are talking apples and oranges here, folks.

Which is why almost all (all?) other cod liver oil manufacturers add antioxidants to slow oxidization.

5. No Antioxidants Added

If you search online, other cod liver oil manufacturers add antioxidants in order to slow oxidation.

Carlson’s adds antioxidants to their cod liver oil:

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So does Nordic Naturals:

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And check out what Rosita Real Foods says about their EVCLO and why they add antioxidants.

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Does Dave Wetzel add antioxidants to FCLO to slow the oxidization? As Grumpy Cat says, Nope.

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Wetzel says he couldn’t see any change in the test results whether he added an antioxidant or not. What this says to me is, probably because it’s already gone rancid. Once an oil goes rancid, you can’t add an antioxidant to reverse the process.


6. “We Don’t Think It Can Go Bad”

PUFAs begin to oxidize during the manufacturing process, but they also oxidize over time in storage. Remember, you can’t stop oxidation — you can only slow it.

For this reason, it is important to store PUFAs in a cold, dark place (refrigerator). This is also why fish oils are bottled in dark (not clear) bottles. You should only buy small amounts of fish oil, for example, a small bottle… and keep it in the fridge.

Here’s a video with Dr. Mercola talking about how to store fish oils… he says they should be refrigerated and goes into detail about how fragile they are and how they will go rancid if not stored properly:

Other cod liver oil companies recommend that you store the cod liver oil in the fridge and use it within a short period of time. Rosita, for example, recommends that you store their EVCLO in the fridge and once the bottle is opened, you should consume it within 30-80 days.

David Wetzel, on the other hand, tells his customers that they can store the FCLO in the cupboard or the fridge. He told me that I could keep my FCLO in the cupboard for “6 months to a year”. He has a number of posts on his website saying that you can store FCLO in the cupboard for extended period…

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So he says traditionally FCLO has not been refrigerated. It should be noted, however, that the FCLO produced was traditionally produced in Norway, an arctic climate. So although the Vikings may have left their FLCO out in a barrel, for most of the year, the climate was very cold to freezing.

In this response to a customer’s comment, Wetzel says: “The enzymatic activity goes on to digest the product.”

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What does that mean exactly? What I think he’s saying there, and comment below if you think I’m wrong… I think he’s saying there is some kind of further “fermentation” (or “enzymatic activity” whatever that means) going on that somehow protects the product from spoiling.

fclo-enzymatic activity

I think we have plenty of evidence here that Dave Wetzel’s advice on the storage of FCLO is fishy to the point of rancidity, but wait folks, there’s more…

One of my readers left a comment with an email she got from Wetzel stating the they mark the sell-by-date as two years. He said, “I’m not sure if it can go bad?”

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On the one hand, Wetzel is always saying that FCLO shouldn’t need labels because it’s a “food”. But if it’s a food, how can it not go bad? Does anyone know of a food that never goes bad? Besides those ancient McDonald’s hamburgers we’ve all seen online?

“While monounsaturates (like olive or peanut oil) also can go rancid after about a year, they are still 10 times more stable than polyunsaturates,” according to lipid specialist and University of Massachusetts professor Eric Decker. (Source)

If olive oil is stable on the shelf for one year, how can we store a PUFA which is 10x less stable, on the shelf for 2 years, or, as Wetzel says, indefinitely?


7. Foul Taste, Strong Smell, Burning Throat

Multiple people have reported that they cannot take FCLO because they find it repulsive, disgusting, and/or it burns their throat. This was allegedly due to the “high enzyme content”. Again, not sure what this “enzymatic activity” is Wetzel talks about.

Common sense tells you that rancid foods smell bad, but many of us have lost the ability to smell and taste rancidity.

According to Kantha Shelke, a food scientist and spokeswoman for the Institute of Food Technologists, “Though some hope that our sense of smell and taste can help us avoid rancid foods, recent studies raise doubts.” She says that “new immigrants to America often think peanut butter — now often made with polyunsaturates — smells rancid while American natives think it just smells like peanut butter.”

So maybe all those folks who say FCLO doesn’t taste rancid to them just have gotten used to it.

8. Many Reports of Trouble with Digesting FCLO

There are many, many reports from people who experienced stomach pains, cramping, diarrhea and nausea and vomiting after consuming FCLO. See the adverse health reports page here.

Again, this correlates with a rancid oil.

9. Vitamin Deficiencies Are Caused By Rancid Fats

A reader sent me this article: Health Effects of Rancid Fat.


Rancid fat can destroy vitamins, which could lead to deficiency. (This would be an indirect health effect of eating rancid fat, since the thing that harms you is the deficiency, rather than the fat itself.) (Source: Pavcek PL, Shull GM. J Biol Chem 146(2):351-5, 1942.)

If you click on the source, it says:

In studies involving the feeding of diets containing cod liver oil and butter fat to rats, some of the animals developed typical symptoms of mild biotin deficiency, i.e. spectacle eye and spasticity of gait, after being maintained on the diet 12 to 16 weeks. It was soon evident that such a ration containing cod liver oil and butter fat was very prone to turn rancid and that this rancidity was responsible for rapid losses of vitamin A.

This would explain the huge number of reports we’ve gotten from FCLO customers who have low vitamin D. I have posted 44 reports so far, and more are coming in.

I have emails from patients of Dr. Thomas Cowan that say he recommended vitamin D3 in addition to FCLO.

Chris Kresser also reported being puzzled by the consistent reports of low vitamin D among his patients who were taking FCLO:

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If we are taking one of the best and most potent sources of vitamin D in the world (arguably the best), why would we need to supplement with more vitamin D?

10. Other Adverse Health Reactions Are Correlated with Consuming Rancid Fats

Finally, there are a number of adverse health reactions being reported that are caused by consumption of rancid fat. Inflammation is one of the most obvious ones…

Go the adverse health reactions page and go to the section on C-Reactive Protein Tests. We have gotten 5 reports so far.

If you know anything about C-Reactive Protein tests (you can Google it), it’s frightening that people are saying their numbers were elevated when they were on FCLO — and when they stopped taking it, their C-RP numbers dropped.


So… Is FCLO Rancid?

I don’t know about you but I’d say there is far too much questionable evidence for any sane person to conclude that FCLO is not rancid.

It’s common sense. Cod liver oil is high in PUFA. You would have to protect for ALL of the above (heat, light, air) and even if you did do all of that, it still doesn’t explain how the oil can sit in fermentation vats for 6 months with no antioxidant added and not go rancid.

Too many questions. Not enough answers. How is the oil protected from rancidity? Is it that special “enzymatic action” Wetzel talked about that somehow magically protects the oil from rancidity? Or perhaps there are elves and unicorns that sprinkle fairy dust on the cod and pollock livers in the “solar activated greenhouse”?

Until Wetzel accounts for all of the above, best to AVOID this product. Just too many unknowns.

I am not a gambler. I used to live in Vegas, but I never gambled a single dollar of my hard earned money. Sure, I take risks in life. But they are calculated risks based on research.

Given everything we know about FCLO, the risks seem outweigh the potential benefits. And gambling with our health is not a game we ever want to play.

Additional Sources (not linked to above):

Please Share Your Thoughts Below

Please comment below with your thoughts about and experiences with FCLO.