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The Definitive Fish Oil Buyer’s Guide


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Update: I now recommend Bio-Avail Omega+ from Adapt Naturals. It’s a blend of ultra-pure fish oil and the most bioavailable forms of curcumin and black seed oil.


Sorry, folks. Another long one. It was unavoidable, though, because I really did want this to be a “definitive guide” that covers all (or at least most) of the relevant issues involved with choosing a fish oil. Here’s a summary for the time-challenged:

  • There are five important factors to consider when choosing a fish oil: composition, purity, freshness, bioavailability, and sustainability.
  • Not all fish oils are created equal. It’s essential to do your homework and make an informed choice. Many fish oils are oxidized or made with poor-quality ingredients and may cause health problems instead of solving them.
  • The potency of various products depends not only upon the levels of EPA and DHA but also upon the molecular structure of the fats in the oil, which in turn affects absorption.
  • Natural triglyceride fish oils are better absorbed than highly purified (i.e. ester) fish oils.
  • Many fish oils are made from fish that are endangered. Choose products made from fish that are certified by organizations such as Friend of the Sea or MarinTrust.


So far in this series we’ve looked at why fish is superior to plant-based sources of omega-3. We’ve examined the importance of reducing consumption of omega-6 fats. We’ve considered how much omega-3 is needed to support health and treat disease. We’ve revealed that concerns about the safety of fish consumption have been overblown, and that eating fish regularly is not only safe but incredibly beneficial. And in the previous article we compared the benefits of eating fish to taking fish oil.

In this final article of the series, we’re going to take a closer look at fish oil. Fish oil is one of the most popular supplements taken by consumers today. Most people who are at least relatively health conscious understand that they need omega-3 in their diet and are probably not getting enough from food (unless they eat a lot of fish).

But why should you consider taking fish oil in the first place? Which fish oils are best? How much should you take? And what should you look for in a good product?

There’s a tremendous difference in the ingredients, purity, freshness and therapeutic benefit of the fish oils available today. The supplement industry is rife with false claims and unsavory companies that are far more interested in profiting on the fish oil craze than they are in your health and well-being.

In this article, I’ll focus more on dispelling common misconceptions about fish oil and helping you to choose the best product for your needs.

My current thoughts on fish oil

My view and recommendations for fish oil have evolved over time.

I’ll tell you what has remained constant first, then tell you what has changed.

I still recommend getting EPA/DHA from the diet whenever possible—either as your exclusive source or as a foundation to build upon.

And I still don’t recommend super-high doses of fish oil, like 10 grams per day. This isn’t common anymore, but there was a time when many health gurus were suggesting this as a way to reduce inflammation. But it’s not supported by research, and there’s no additional benefit beyond the 1-3 grams a day studies suggest is the best therapeutic target.

What has changed is my growing appreciation for the role fish oil can play in ensuring adequate EPA/DHA intake for many people. For all of the reasons I’ve mentioned in this series, many folks are just not getting enough EPA/DHA, and taking a fish oil supplement is probably the only way they’re going to get these critical fatty acids.

It’s also true that some people benefit from greater amounts of EPA/DHA than they can easily obtain in their diet.

My specific recommendations for EPA/DHA supplementation have also evolved. I have recommended cod liver oil for many years, and I still do today. It’s a good option because it contains vitamins A and D in addition to EPA/DHA.

However, the amounts of EPA and DHA are lower in cod liver oil than in most fish oil supplements. And if you’re already consuming organ meats like liver or an organ meat supplement, like Bio-Avail Organ from Adapt Naturals, you don’t really need (or even want) the additional A/D from cod liver oil.

This is why I now recommend a high-quality fish oil supplement for people who are either not getting enough EPA/DHA from their diet or who would benefit from additional EPA/DHA because of a chronic, inflammatory, or autoimmune condition.

But finding a high-quality fish oil is easier said than done. The global market for fish oil is north of $2 billion now. Whenever there’s that much money to be made, you can be sure all kinds of shenanigans will ensue!

So, let’s look at some of the most important factors to consider when buying fish oil.

Factors to consider when buying fish oil

There are five primary variables to be aware of when shopping for fish oil:

  1. Composition. In order to have the desired anti-inflammatory effect, fish oil must contain an adequate amount of the long-chain omega-3 derivatives EPA and DHA.
  2. Purity. The oil must meet or exceed international standards for heavy metals, PCBs, dioxins, and other contaminants. Many do not—even when they claim they do.
  3. Freshness. The oil should be fresh and not rancid. Rancid/oxidized oils promote oxidative damage and increase inflammation, both of which are risk factors for nearly every modern disease. Sadly, many fish oils on the market contain high levels of oxidative by-products.
  4. Bioavailability. The ability to absorb the beneficial components of fish oil is based on the molecular shape of the fatty acids. The more natural the structure, the better.
  5. Sustainability: The fish should be harvested in a sustainable manner, and species that are under threat should be avoided.


Composition refers to the overall concentration of EPA/DHA and the ratio of EPA to DHA. To some extent, this depends on the goal of taking fish oil. For example, some conditions may call for a higher proportion of DHA, while others benefit from more EPA.

Most studies suggest that a 3:2 ratio of EPA to DHA is optimal, with a total amount of omega-3 ranging between 500 mg and 2 g per day.

The optimal amount for each person will vary based on several factors, including how much fish/seafood you’re consuming in your diet. If you don’t eat any, and/or you have an inflammatory or autoimmune condition, you want to aim for the higher end. If you eat some fish/seafood, you can aim for the lower to mid-range.


Many species of fish are known to concentrate toxic chemicals like heavy metals, PCBs, and dioxins, which can cause serious diseases, especially in children and developing fetuses. In a previous article, I explained how these chemicals are typically not a concern when eating whole fish because fish also contains selenium. Selenium binds to mercury and makes it unavailable to tissues, thus protecting against any damage it may cause.

And while fish constitute only 9% of our dietary intake of dioxins and PCBs, high doses of fish oils taken every day (as is often recommended) may raise this percentage significantly and expose us to undesirable levels of these toxins.

To address this, fish oil manufacturers use a process called molecular distillation to remove the toxins from the oil. When done correctly, molecular distillation is capable of reducing the toxins in fish oil to levels considered to be safe by the EPA and other agencies.

Although almost any fish oil manufacturer will tell you their product is free of these toxins, independent lab analyses tell a different story. In March of 2010, a lawsuit was filed in California court against the manufacturers of ten popular fish oils because they contained undisclosed and (possibly) unsafe levels of contaminants.

Unfortunately, this kind of deception is all too common in the supplement industry. The best companies will be able to provide a Certificate of Analysis (COA) from the manufacturer upon request. A COA is an analysis performed by an independent lab to measure the ingredients of a product and confirm whether it lives up to the claims made by the manufacturer.

If the manufacturer won’t provide a COA, I start to get suspicious. This is standard practice in the industry, and there’s no reason they shouldn’t be happy to show you theirs.

In general, fish that are lower on the food chain, like sardines and anchovies, naturally have a lower concentration of contaminants. For this reason, it may be wise to look for a product made from these fish.

So what levels of these toxins are safe? As you might imagine, there is some disagreement on this question since there is no single governing body that determines acceptable levels. However, the standards that are most often followed by fish oil manufacturers are summarized in the table below.

fish oil toxin standards

* ppt = parts per trillion
* ppb = parts per billion

The best fish oils will not only meet but exceed these international standards.


I have written extensively about the dangers of oxidized, rancid oils. They promote oxidative damage and increase inflammation, both of which are risk factors for nearly every modern disease.

The more unsaturated an fat is, the more vulnerable it is to oxidation. Long-chain, omega-3 fats found in fish oil are the most unsaturated of the fats, and thus the most susceptible to being damaged.

This is why it’s crucial to ensure that the fish oil you select is fresh and not rancid. Once it has gone rancid, it will have the exact opposite effect on your body than you want it to.

The first thing to do is to check something called the “peroxide value” on the COA. This is a measure of rancidity reactions in the oil that have occurred during storage. It should be less than 5 meq/kg.

If this checks out, and you decide to order that product, break open a capsule once you receive it. There should be no “fishy” odors. They should smell like the ocean, but not like rotten fish. They should also not have a strong lemon or lime scent, which could be an indicator that the manufacturer is trying to mask the rancidity.

The p-anisidine value measures secondary oxidation products. The IFOS and GOED standard is less than 20 units. However, it’s important to note that p-anisidine is not appropriate for measuring secondary oxidation in omega-3 oils that have a strong color or contain added flavorings.

For example, salmon oil contains carotenoids, which have a natural yellow/orange coloring. Bio-Avail Omega+ from Adapt Naturals contains curcumin, which also has a natural orange coloring. This throws off the p-anisidine values and makes it an irrelevant test.

TOTOX is the last way to measure oxidation. It’s simply a combination of the peroxide and p-anisidine values. (For this reason, it’s also not appropriate for products with a strong color.) The IFOS and GOED thresholds are 19.5 and 26 meq/kg, respectively. But the best products have TOTOX values below 15 meq/kg.

Finally, some studies have shown that adding antioxidants (e.g. curcumin or resveratrol) to fish oil can improve stability.

A common misconception is that you can determine the quality of fish oil by freezing it. The theory goes that if you freeze the oil and it is cloudy, it’s rancid. That is not the case. All fish contain saturated and monounsaturated fatty acids, albeit in small amounts. These fatty acids make the capsules appear cloudy when frozen in products that contain whole fish oil.


This is another area surrounded by significant controversy. Some argue the levels of individual constituents in fish oil aren’t paramount. Scientists discovered the healthful effects of omega-3s by studying people with fish-heavy diets, before supplemental fish oil even existed. Clinical trials using supplemental fish oils over the past few decades have contained widely variable levels of both long-chain omega-3 derivatives (EPA and DHA), and not super-high concentrations of either or both.

However, due to poor conversion of ALA to EPA and DHA, unless you are eating fish it is very likely you are deficient in long-chain omega-3s.

Following this line of reasoning, the DHA content in particular of fish and fish oils does seem important if we wish to obtain the best possible therapeutic effect. Many recent studies demonstrating the anti-inflammatory potential of fish oil used a daily dosage of DHA in the range of 1-3 grams. What’s more, foods like salmon roe that have been prized by traditional cultures for their nourishing and healing effects contain large amounts of DHA. A single 6 oz. serving of salmon roe contains 1 g of DHA. (In fact, this would be the best way by far of supplementing with DHA if money were no object. (Unfortunately, wild salmon roe goes for about $28/serving.)

The suggested DHA dose will of course depend upon the condition being treated. If you have a chronic inflammatory condition (heart disease, arthritis, Crohn’s or ulcerative colitis, etc.) I would suggest taking between 1 and 2 grams per day. If you are taking it simply for health maintenance, 500 mg is probably sufficient.

Unfortunately, many fish oils do not have significant amounts of DHA. This means you’d have to take an impractically high number of capsules each day to obtain the therapeutic dose. This is not desirable, since all unsaturated oils (including fish oils) are subject to oxidative damage. We don’t want to take large quantities of them for this reason.

Remember to check the label and ensure that your product has approximately 200-300 mg of DHA per capsule. This will allow you to achieve the therapeutic dose by taking no more than 3 capsules twice a day.

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The ability to absorb the beneficial components of fish oil is based on the molecular shape of the fatty acids. In short, the more natural the structure and the less it is chemically altered, the better.

This is true for any nutrient, of course, and it explains why I am always in favor of obtaining nutrients from food or food-based sources when possible. Each additional step in processing from the natural state of food to extract or isolate nutrients introduces the potential of damaging the nutrient or changing its chemical form so that it’s more difficult to absorb or affects the body in a different way.

When it comes to fish oils, there are three forms currently available on the market:

  1. Natural triglyercide oil. This is what you get when you “squeeze” the whole fish and extract the natural oil from it. It is the closest to eating fish oil in its natural form and is highly bioavailable. The drawback of this form is that, because it’s not concentrated, it usually has low levels of EPA and DHA. And because it isn’t purified, it can have high levels of contaminants such as heavy metals, PCBs, and dioxins.
  2. Ethyl ester oil. Occurs when natural triglyceride oil is concentrated and molecularly distilled to remove impurities. The ester form is still in a semi-natural state because it is the result of a process that naturally occurs in the body. The advantage of this form is that it can double or triple the levels of EPA and DHA.
  3. Synthetic triglyceride oil. This form occurs when natural triglycerides are converted to ethyl esters for concentration (as above) but then re-converted into synthetic triglycerides. The original position of the triglyceride’s carbon bonds changes, and the molecule’s overall structure is altered, which impacts the bioavailability of the oil.

Studies on absorption of the various types of fish oil suggest that, unsurprisingly, the natural triglyceride form is absorbed better than the ethyl ester form, which in turn is absorbed better than the synthetic triglyceride form.

One study by Lawson & Hughes in 1988 showed that 1 gram of EPA and 0.67 grams of DHA as natural triglycerides were absorbed 3.4 and 2.7 fold as well as the ethyl ester triglycerides.

In the previous article, we saw that fish oils were better absorbed when taken with a high-fat meal. In another study by Lawson & Hughes later the same year, they showed that the absorption of EPA & DHA from natural triglycerides improved from 69% with a low-fat meal (8g total fat) to 90% with a high-fat meal (44g total fat). Absorption of both EPA and DHA from ethyl ester oils was increased three-fold from 20% with a low-fat meal to 60% with a high-fat meal.


Our global fisheries are in dire straits, and fish oil is a big business. So, it’s crucial to choose a product that is manufactured with sustainability in mind and that has a fully transparent and traceable supply chain.

The easiest way to do this is to choose a product that is certified by organizations like Friend of the Sea or MarinTrust, two of the leading organizations for sustainable and responsible fishery management.

I would also choose a supplier/manufacturer with practices that minimize waste and its environmental impact.

For example, rather than catching fish that is only used to produce fish oil, some producers instead use fish meal to make the oil. This eliminates one of the main concerns about fish oil, which is that it will further deplete fisheries.


As a Functional Medicine clinician, author, and educator, I’ve been following the fish oil market closely for many years. I’ve used several different fish oils with my patients. I’ve read hundreds of studies on the purity, freshness, composition, and benefits of fish oil. I’ve spoken to industry experts and insiders, and I know what many companies do to cut corners and save money (at your expense).

When I started my own supplement company, Adapt Naturals, I knew that one of the first products we’d make would be fish oil. I wanted to create a product with the purest, freshest, and most sustainable fish oil available. And that’s exactly what we did with Bio-Avail Omega+.

I chose VivoOmega from GC Rieber as our fish oil. As the chart below illustrates, it significantly exceeds international standards for both purity and freshness.

Purity and freshness are critical. But I didn’t stop there. Most people who take fish oil are taking it to achieve certain outcomes, like better muscle and joint health, increased mental clarity, a more stable mood, clearer skin, and more balanced immune function.

So, when I formulated our fish oil product (Bio-Avail Omega+), I added the most bioavailable forms of two powerful nutrients that also support these goals: curcumin and black seed oil.

Now you can get the benefits of all three of these superfood nutrients in a single, two soft-gel daily serving.

Bio-Avail Omega+ contains an optimal composition of EPA and DHA (510 mg of EPA and 330 mg of DHA, a 3:2 ratio). It is made with triglyceride oils for optimal bioavailability and absorption. And it is produced with the most sustainable and traceable fish oil material in the industry. (See this page for more info.)

I’m proud of this product. It came directly out of my experience working with patients for 15 years and my extensive research into what is most important in a fish oil product. I hope it helps you to achieve your health goals!

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Join the conversation

  1. I’m not contesting the greater bioavailability of TG over EE. That is rather indisputable, in my opinion, and it’s why EE fish oils were illegal in Canada for many years (though they’ve loosened restrictions recently). There are even more studies on this than you cite here. What I think is rather dubious is the notion that synthetic triglycerides are somehow structurally different than natural triglycerides. While the ethyl alcohol base in EE is a poor candidate for pancreatic lipase, so-called synthetic triglycerides are simply omega-3 fatty acids bonded to a glycerol alcohol base via covalent carbon bonds, just like the natural form. The only “position” that could possibly change is the bending of the fatty acid tail, but as that study I cited showed, that’s irrelevant to pancreatic lipase, which is at the heart of the bio-availability discussion. While I’m sympathetic to the “natural is better” mindset and have adopted it myself, I do recognize that not all processing is bad. In this case, all that has happened is that the alcohol base has changed from glycerol to ethyl then back to glycerol. I believe that your source for that claim had less than innocent motives.

  2. Bravo! I maintain a blog about fish oil where I chronicle all the latest research on the benefits of omega-3 from fish oil supplements and I have to say that you have some of the best articles on omega-3 I probably have ever come across! (except my own, of course :-D)

    Allow me to be the healthy skeptic now and raise a few points:

    1. There’s no research that I’m aware of that supports the notion that the absorption of synthetic triglycerides is impaired relative to natural triglycerides. The only mention of this is from Xtend-Life discussing it in the context of supporting their product over other products (and it appears you stumbled across their Buyer’s Guide too… 😉 Furthermore, there’s nothing to support the assertion that the carbon bond position of synthetic TG has been altered. If you assume they mean the ester bond, which is where pancreatic lipase acts to break down the triglyceride, then what are our choices for carbon bond positions? Either the carboxyl group has a covalent bond with the first carbon of the fatty acid tail, or it doesn’t. Am I missing something here? I suppose he could mean stereoisomeric triglycerides, but as this study shows, pancreatic lipase doesn’t really care which way the tail bends:


    2. It’s interesting to note that the absorption rate of free acids, which aren’t bound to an alcohol base, has been show to be almost twice as high as TG:  ( http://www.ncbi.nlm.nih.gov/pubmed/2144420). I suppose they’re probably too unstable to be bottled and sold, however.

    3. Krill oil has been touted by people like Dr. Mercola as being free from the toxins that fish are susceptible to, but that’s flat-out wrong according to multiple studies. (such as http://www.ncbi.nlm.nih.gov/pubmed/16183185)

    4. There is actually a voluntary testing and certification program called the International fish Oil Standards program, or IFOS. I recommend that people only buy fish oils that have every batch certified by IFOS because they are far more strict than most governing bodies. The reason they’re more strict is because this allows for much higher doses to be taken when trying to treat chronic or severe conditions.

    I’m sure I will think of more too. 🙂

    • Marshall,

      1. The literature is mixed on this, but this paper and this one both show higher absorption of natural triglycerides than ethyl esters. The second one shows that the absorption of ethyl esters improves with a high fat meal, as I stated in the article. There are other papers showing they are equally well absorbed. But what isn’t controversial is that triglycerides from whole fish are better absorbed than triglycerides from fish oil in any form. I prefer to take products in their least processed, most natural form, so in general I’d choose a natural triglyceride oil over an ethyl ester oil – provided it met standards for purity.

      2. Yes, FFAs are too unstable to use in supplement form.

      3. As I said in my article, I’m ambivalent about krill oil. I need to see more independent studies before I make up my mind.

      4. Thanks for the tip in IFOS.

    • Unfortunately Dr Mercola has been wrong on so many occasions that I’ve moved him from nutritionist to alarmist.

    • In general we absorb oils better than capsules. One less step for our digestive system to go through.

  3. Hi chris, thanks for all the great reading
    I read that cooking meat or fish at high temps can destroy some of the omega 3.  Any thoughts on that?
    Its interesting what you wrote about DHA reducing pro-inflammatory cytokines. I have an assignment for my acupuncture study looking at the effects of acupuncture on rheumatoid arthritis and it seems to work on the same things (cytokine TNF a etc)  via the vagus nerve.  So both fish oil and acupunture could be good for such inflammatory conditions.

    • Yes, cooking at hight temps does destroy some of the n-3. They are very fragile and susceptible to oxidative damage. Best to eat some fish raw, or to cook moderately.

      There’s a lot of research on the anti-inflammatory effects of acupuncture. Adenosine is another potent mediator, and if you search for “acupuncture adenosine” in Google scholar there should be a couple of good papers that might interest you.

  4. You’ll be fine.  Keep in mind, though, that some people can’t synthesize D from sunlight very well.  Age and inflammation are two factors that inhibit conversion.  Best to have your levels checked to see if what you’re doing is working.

  5. I found Jarrow “EPA-DHA Balance” at Whole Paycheck today so I bought some. It claims 420mg EPA and 210mg DHA (or 2:1) per capsule or “softgel”. Of the various and silly-expensive options there this had the highest DHA. So my plan is to take two a day along with two a day of WF-brand cod liver oil for vitamins A and to a much lesser extent D; I’m gonna get most of my D from sunlight, at least until winter.
    I’m not interested in the Green Pastures or Vital Choice supps because I think the prices are outrageous. “Oh you can’t put a price on health!” Oh yes you can.

  6. Alan,

    I just came across some research suggesting that the optimal ratio of vitamin A to vitamin D is between 5-8:1.  This is roughly what you’d get by following the suggestions I listed above.

  7. Chris,
    Since the Green Pastures FCLO and Vital Choice Wild Salmon Oil both contain Vit D and Vit A, I was wondering what amount of Vit A one should try not to exceed. I know how much Vit D I need to consume to keep  my Vit D blood tests in a good range. I am not sure how much Vit A should be consumed.  What is you opinion on the matter.
    I have learned alot from your blog, Thanks for all the hard work 

    • A normal dose of the FCLO and/or Wild Salmon Oil plus maybe eating a serving of beef liver once a week would be a good goal to shoot for with vitamin A.

  8. Andrew Stoll (Harvard, “The Omega 3 Connection) says that EPA is the critical element. “EPA is the omega-3 fatty acid with anti-inflammatory actions and promotes heart and joint health,” (from the OmegaBrite web site where Dr. Stoll sells his Omega 3 pills).
    It seems to me that the science on this shows mixed results and that for now, if you supplement, it should be both EPA and DHA. But I’d like to know more about your reasons for preferring DHA and the research behind that.
    Also, ConsumerLabs.com has tested a dozen or so Omega 3 supplements and gives them ratings based on the tests, which include testing for contaminants. This looks like a good source for finding a supplement that meets your criteria.
    This series, by the way, has been excellent and I’ve learned a great deal. I’ve started eating fish again, which I stopped doing because of all the reports of dangers.

    • Gary,

      Thanks for your comment. I explained why I believe DHA may be more important in the first article in the series. In addition to what I wrote there, in vitro studies demonstrate DHA is superior to EPA in inhibiting the expression of inflammatory markers such as pro-inflammatory cytokines, monocyte adhesion to endothelial cells, and cell-adhesion molecules, particularly vascular cell adhesion molecule-1, intracellular adhesion molecule-1, and E-selectin.

      Data now demonstrates DHA has important hemodynamic and anti-atherogenic properties. In terms of cholesterol and lipid metabolism, DHA (but not EPA) increases HDL cholesterol and increases LDL particle size, both protective against heart disease. DHA, but not EPA, can also significantly reduce heart rate, blood pressure and platelet aggregation.

      Evidence also suggests that DHA plays a more important role in brain health and visual acuity, especially in developing fetuses and infants. DHA deficiency has been linked to Alzheimer’s and cognitive decline.

      I agree that the data is mixed, and I could be wrong about this. But a lot of the newest evidence, as well as anthropological evidence, points towards DHA. In any event, if you take Wild Salmon Oil or Cod Liver Oil as I suggest, you’ll get a good amount of both.

      • I’ve been taking fish oil for about five months to lower my triglycerides and blood pressure. And it worked very well.

        However, my sensitivity to light has worsened dramatically, even in somewhat darkened rooms.

        This study seems to suggest that DHA may be the culprit. I’d be curious to hear your interpretation:


  9. All Seal products are banned in the US since the Marine Mammal Protection Act (MMPA) was enacted in 1972 in order, mainly, to protect the 600,000 dolphins which were killed by tuna fishing operations each year.   The Canadian Harp Seal population is estimated to be between 6.4 and 9.5 million animals, and the annual quota for hunting is about 300 thousand.  So it’s not an issue of sustainability, as the seal population is one of the healthiest of any marine stock.

    • Thanks for clarifying this, Kevin. So the only question, then, is the EPA and DHA levels. You may have to take a bit more of it than you would the salmon oil or cod liver oil to get a therapeutic effect, but otherwise it sounds fine.

  10. What about Seal oil?  I think it’s banned in the USA, but it’s available here in Canada.  You can get it for as little as $15 for 300 500mg gelcaps, each containing 40mg of EPA, 50mg of DHA, and 25mg of DPA.

    • I don’t know much about seal oil, but the same criteria I outlined in the article would apply. Those are fairly low numbers for EPA and DHA, though, so even if it’s well absorbed you may have to take quite a bit of it to benefit. I also question the sustainability and environmental impact of it if it is banned in the U.S.

  11. You need to calculate the amount of the useful component per unit of product.  The concentration, like you said.  Because every pill is a different size, and “serving size” is made up.
    Each pills varies in size and concentration and composition.  I’ll spoil the results for you: That Vital Choice is 15% EPA+DHA.  That Jarrow is 48% EPA+DHA. NOW ultra omega is 75% EPA+DHA.  And it is a 2:1 ratio of EPA:DHA commonly used in studies because it is commonly found in fish.
    PS: the better absorption of undistilled oil is irrelevant because undistilled oil is a cocktail of contaminants.  No doctor recommends supplementing with extra PCB and heavy metal.  Every government in the world recommends capping even whole fish consumption very aggressively.

    • I’ve addressed all of your comments extensively in the other articles in this series. Please read them here.

      I’ve made the case that DHA is more important than EPA for several reasons. See here. Also, there’s a lot of evidence suggesting that oxidation of EPA contributes significantly to aging.

      The better absorption of natural oils is not at all irrelevant. Vital Choice Wild Salmon Oil is under the acceptable levels on all contaminants. So is the FCLO. Both of these oils have other nutrients and co-factors that the purified oils don’t have, as I pointed out. EPA & DHA aren’t the only considerations.

      Concerns about contaminants in fish have been way overblown, as I described here.

  12. Chris,
    Thanks for the quick response to my question about Vitamin’s A and D. I will need to spend some time reviewing the evidence.
    Perhaps I should do an interventional study with n=1, on myself. Take D alone, and then take it with A, then drop the A out again, and see how my 25(OH)D levels vary. Maybe there’s an easy way to measure blood levels of A. I’ll have to look into this.
    Regarding the HDL, I guess I confused the matter even more because I “corrected” your text to what I thought it should have been by capitalizing the word “INCREASED.” Your text has “reduced.” Your comment above suggests that my interpretation was correct.

  13. Thank you for this list!  I have bleeding issues with EPA and it never occurred to me that a fish-based omega-3 supplement existed that was predominantly DHA with so little EPA.  This may work very well for my son and me and if it does, I’ll recommend it to my mom too.

  14. Thanks for all the info Chris.
    I went to vitacost to take a look at the Jarrow product you listed and found another Jarrow product called “Jarrow Formulas Max DHA Liquid Delicious Lemon” which might be better. It is still DHA dominant (750 mg DHA/450 mg EPA) but not as much as the capsules.
    I’ve been using Carlson’s liquid fish oil, but I think I might give this Jarrow product a try in my next order.

    • Thanks for the tip on the Jarrow DHA liquid. One potential issue for some is that it contains soy. However, unless one has a true allergy my guess is that the amounts are minimal. 2 tsp. of this oil give you up to 1.6g of DHA, so it seems like a good choice – especially for those who have trouble swallowing the fish oil capsules. The reviews say that kids will take it, which probably means that the taste isn’t too objectionable.

      • This is exactly what I was looking for in the comments. I need a liquid form! Can NOT do the capsules unfortunately. Will check out the Jarrow. Thanks for this article.

  15. Nice article. I appreciate the thorough research embodied in it. I plan to make some purchases based on your recommendations.
    I was surprised by your endorsement of cod liver oil. Would you like to address the citations presented by John Cannell asserting that the Vitamin A in liver negates Vitamin D activity?
    P.S. Here’s another job for the proofreader (or I misunderstood it):
    ” There was a moderate decrease (of 3%) in HDL, but HDL was still significantly INCREASED from baseline.”

    • Moises,

      That’s not a typo. What I was saying is that HDL decline by 3% on the maintenance dose from the high point it reached during the active treatment phase of the trial, but even after that 3% decline was still significantly elevated compared to where it was before any treatment. Make sense?

      Regarding Cannell’s assertion about vitamin A, I don’t buy it at all. None of the studies he refers to suggest causation – they only show correlation. Correlation is not causation. Remember that the confusion of the two is what confounded cholesterol research for decades and led us down a ridiculous dietary path.

      Read these articles for more:

      Vitamin A does compete to some degree with vitamin D for absorption, but on the other hand vitamin A is an important co-factor for the absorption of vitamin D.

      In situations where science and evolutionary nutrition conflict, I’m far more likely to trust what our ancestors ate.

  16. I have been using Source Natural’s omega 3 fish oil capsules.  When I contacted them for the COA customer service told me that Artic Pure (supplier of the oil) would not give the COA to consumers.  If that remains the case, this consumer will go elsewhere.

    • Thanks for updating us on the Source Natural product, John. It could be that it’s fine, but as I said, I get very suspicious when they won’t provide a COA. Since there are plenty of other companies that will, I don’t see a reason to buy from one that won’t.

      • Hi Chris,

        I am curious to know that I have knee joint pain (Osteoarthritis); in this condition which Fish Oil (Cord Liver or Salmon) would you suggest.

        Appreciate your help.


  17. Thanks for distilling all your research, this is very helpful!
    There is a typo:
    …ethyl ester form, which in turn is absorbed better than the ethyl ester form

    • Thanks for catching that. Clearly my proofreader (ah hem, that’s me) is overworked.

    • I am surprised that Green Pastures Fermented Cod Liver Oil is recommended when at the same time it is not recommended to consume an oixidised supplement. We have analysed this oil in our lab. and come to the conclusion that this oil is so oxidised that peroxide values are already at stage 2, meaning that you cannot measure peroxide value anymore as a stage 2 oxidation is difficult to dedect in measurements. This raw material is brought in frozen (not fresh) and “fermented” for months until finally the oil remainders from the raw materieal is taken out and bottled. Oxidation provoces free radicals and is hazardous to your healt. The activity happening during the months of so called “fermenting” is in fact oxidation. If you taste the oil it is totally rancid which proves the point. Also the colour is at stage 15 while GOED limits states 5. The dark color represents impurity and probably blood from the raw material which also speeds up the activity level of oxidation. This oil does not meet US pharmacopeia standards on several levels. A pure and fresh cod liver oil should have a clear and light yellowish color. It should not smell or taste rancid, but have a slight smell of sea and really no other taste than a regular rapseed oil for cooking for instance. I hope that Green Pastures is taken off the market as it is an insult to companies that work against oxidated supplements.

      • @ Randi I think you bring up some excellent points here. What would you recommend and why? Did your lab publish the results on the Green Pastures at all or some place else? Can you cite anything?
        I have to avoid fermented everything. Thanks for giving me the heads up on this.

        • I would recommend for instance the products from Nordic Naturals, I know they are careful with raw material selection (it all starts there,… freshness and purity). Also a very exclusive looking product called “Omega cure” is in fact not only expensive looking, but also a tremendous quality product. It is bottled so you can taste it, this producer also has a vanilla taste which curious enough tastes very good. For a vanilla to taste good in cod liver oil, the oil must be of a exeptional quality.

          Results found on Green Pastures are not published, they were done in a private lab.

      • Randy, thank you for this information – is there any way to access this report? I’ve long suspected this about Fermented CLO and have scratched my head as to its popularity.
        I have many patients who take this and would love to be able to cite some facts about the product. Thank you!

      • Randi,

        Green Pastures Fermented CLO has a number of well-respected supporters, but I don’t remember ever seeing any of them refer to a third party lab analysis for safety information. For example, here’s a link to the Weston A. Price Foundation’s “Cod Liver Oil Basics and Recommendations” article with updated 2013 products that include Green Pastures: http://www.westonaprice.org/cod-liver-oil/cod-liver-oil-basics.

        Here’s a link to a 2009 post on the Green Pastures website by Dave Wetzel, one of the founders, regarding peroxide levels: http://www.greenpasture.org/fermented-cod-liver-oil-butter-oil-vitamin-d-vitamin-a/peroxide-value/?back=javascript:history.back(). Wetzel claims that peroxide levels are extraordinarily low. Has PIXE tested it?

        You raised an excellent question: Is Green Pastures Fermented CLO rancid? I’m guessing from your posts that you are not American and not an academic. It would be most helpful if you would substantiate your claims concerning the product. If it’s provably rancid, people should know.

        • I am not an academic within the field, but I have worked in marketing within the same field through many years, and have therefore worked closely with labs and have inside knowledge of raw material treatment. First of all; simple principle and no science… If what comes in is not good, what comes out cannot be good either. When Green Pastures produces it’s cod liver oil in the USA, I also know that it must be an importet raw material. Probably russian as no Scandinavian countries export cod liver oil to the US. Knowing what russian cod liver oil consist of, I refuse to accept that the product coming out of it can be good. This raw material is not selected, meaning that a great deal of blood is still inside the liver. This is why the color of this cod liver oil is so dark. These impurities produce obviously oxidation immediately, and second the oil is NOT produced from a fresh raw material. Acedemics tend to focus mainly of the components of the oil in terms of EPA and DHA, but does it work if the oil is oxidated? There are numerous publications and reports about oxidated omega-3 products. Just search the net. Read for instance the publications written by a doctor with many years of experience in the field.


          The only problem with badly oxidated products is that when it get into stage 2 or 3 it is difficult to measure the peroxide value. There is unfortunately in marketing a lot of focus on EPA and DHA levels. Omega-3 leves will vary depending on the bases of the raw material. For instance an 18/12 oil from anchoveta/South America, has a higher level than cod liver oil, and tuna oil an even higher level. The question is; does it work at all if the oil is oxidated? Why not focus on low oxidation, and less on EPA, DHA. It is only a matter of a slightly bigger daily dose, and at least you are safe that you are not taking anything that may be harmful to you. Everything starts with the raw material….is ith fresh…is it pure…and what is the origin? If the source of the oil is not from a factory that actualy has access to fresh raw material, well selected, and controlled during logistics and the refining process itself, you cannot be sure that you are getting a non oxidated product.

      • Randi, you sound like a salesman for Nordic…

        Anyways, coming from a microbiology background, let’s keep in mind that fermentation is simply controlled putrefaction. Presumably the livers are covered in a salty brine and oxygen from the air cannot attack and oxidize the fats of the livers. Whereas kimchi and sauerkraut use naturally present microbes for fermentation, other ferments control the microbes by adding them in. Think of brewer’s yeast for beer, baker’s yeast for bread, or whey from homemade yogurt added to homemade pickled carrots. I wonder if Green Pastures’ batch to batch quality couldn’t be improved by adding in particular microbes they wish to favor (such as from whey). At present it sounds like they use naturally present microbes :-/ Let’s also keep in mind what we mean by oxidation. When chemical bonds are broken or formed, one chemical is oxidized (loses electrons) and another is reduced (gains electrons). And this will certainly occur during fermentation. But the oxidation we’re worried about is more from oxygen radicals and ambient oxygen, further provoked under high heat. In contrast, a ferment should be an anoxic (oxygen-less) environment (it is, after all, covered in brine) and a low temperature environment. I wonder if Green Pastures soaks and then rinses their livers before fermentation. That would certainly reduce any remaining blood, and is standard practice for liver mousses and whatnot. Additionally, it is safest for the livers to be frozen for shipment, and would be expected to result in a higher quality product by preventing uncontrolled putrefaction during shipment. Freezing does not promote oxidation, but rather impedes it. So, from a purely ‘academic’ standpoint, I do not see your argument for why this product should be oxidized. It might be able to be improved by first rinsing the livers to remove any blood and then seeding the ferment with better-tasting bacteria. Cause, yah, as it is now, it’s nasty stuff.

  18. Thanks for this info!  I realize you made a point of saying that this is not an extensive list; still, I’m surprised that Nordic Naturals is not on here.
    P.S. Enjoyed your recent interview with Stephen!

    • I agree! After doing my own research (I sell supplements/body care in a whole foods cooperative, and am an RN) I have come to the conclusion that Nordic Naturals is a very quality product. They do provide a Certificate of Analysis for each lot, and they are eco conscious. I was not fully sold until I talked extensively with the local sales rep (I know, they are good at selling their products…) but she gave me some great advice and also debunked the FCLO craze. It had read that it was helpful with keratosis pilaris, but she said Nordic Naturals doesn’t produce one for a good reason! My favorite right now is the Ultimate Omega. Total omega-3’s: 1280mg, EPA 650mg and EPA 450, other omega-3’s 180mg. Price is around 35-45 dollars (30 or 60 gel caps). My ONLY gripe is they use gelatin 🙁 I’m making an exception because of the benefits of omega-3’s. As a disclaimer, I am of no affiliation with NN and I am not providing medical advice as an RN.

      • I am also a bit confused. The study that Nordic Naturals is siting on their website http://www.nordicnaturals.com/en/About_Nordic_Naturals/Press_releases/279/?ID=85 certainly used re-esterified oil which I understand from Chris’ article is now the synthetic triglyceride form not the natural TG form that Nordic is claiming. My question is why would companies go to enormous expense to re-esterify if this is not more beneficial or bioavailable? This oil is so much more expensive for the consumer as well. The study contradicts what Chris has said in his article. Or am I missing something here?