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Omega-3 Fatty Acids

Krill Oil Misinformation

written by Vin Kutty

comments 22 comments

best krill oil

Krill oil supplements are supposed to be protected from rancidity by the natural antioxidant astaxanthin…but astaxanthin is very sensitive and quickly degrades to almost nothing. This leaves krill oil exposed to oxidation and rancidity.Nutritional misinformation (intentional or not) is very common on the internet. Here are two examples, with a focus on krill oil.

I got several emails about the Dean Ornish piece in the NY Times where he once again blames all our ill health on fat and meat.

(No, Ornish did not talk about krill oil, but misinformation is misinformation, whether it’s about meat or krill oil.)

As always, I am amused and annoyed by poorly supported science pieces. (Perhaps some of you reading this find that ironic…?) Most people will take Ornish at this word. Even scientists with PubMed access may not look up the references to fact-check thoroughly. If you did that, you’d be amused and annoyed too.

This is too big a subject to tackle here and now, but I’ll say this: Ornish’s intervention works because it is multi-pronged: besides avoiding meat, they tell people to strictly avoid sugar, flour, processed foods, Omega-6-rich vegetable oils, and eat a lot of vegetables and some fish oil, manage stress, exercise, and get supportive counseling. And he blames just meat and fat for all you ailments?!

I think patients who follow Ornish’s protocol notice improvements DESPITE meat avoidance, not BECAUSE of it.

krill oil label

I would alter his protocol by replacing some of the cruciferous veggies with probiotic-friendly root veggies and tubers, adding pastured eggs, lots of seafood, occasional liver, grass-fed butter and yes, some red meat. If you took the ancestral people I talk about in this recent previous blog and hypothetically put them on the Ornish diet, I’m guessing they’d develop several modern diseases.

But your average Homer Simpson will thrive on an Ornish diet…initially at least. Bill Clinton, anyone?

An annoyed Dr. Michael Eades points out some of the major flaws with the Ornish approach here.

A krill oil video

In the same vein as the Ornish piece, I saw a video about why krill oil is better than fish oil. Also by someone apparently widely followed.

See the video for yourself here:  It’s called Battle of the Omega-3 Fatty Acids: Krill Oil vs Fish Oil.

Like the Ornish piece, the disturbing thing here is how smoothly facts and almost-facts are weaved together. I’ll try to sort them for you.

Here are questionable facts from the video above:

  • There is a rumor going around that fish oil actually thins your blood and so does krill oil. And it does.
  • When I take too much krill or too much fish oil, I actually get nose bleeds because they thin your blood so effectively.
  •  Fish oil tends to be less stable than krill oil because krill oil contains astaxanthin.

These krill oil claims are not new. They originated from marketing departments of the first krill oil manufacturers. Even Dr. Mercola holds some of these (perhaps convenient) beliefs too. Unlike Ornish, the nutritional arrows of Mercola and Asprey mostly point in the right direction. That’s the surprising bit.

Let’s look at the disputed (boldface or is it bald-face?) sentences in more detail.

“There is a rumor going around that fish oil actually thins your blood and so does krill oil. And it does. When I take too much krill or too much fish oil, I actually get nose bleeds because they thin your blood so effectively.”

Well, this is kind of a half-truth. So I half object.

Yes, in extremely high doses, fish oil can cause some blood thinning. In this instance, we don’t know how much ‘too much’ refers to. If you are a ‘bio-hacker,’ your variables are multiple. Blaming it all on Omega-3 may be just convenient and semi-supported.

If you look at the science (and this has been pretty well studied) the reality is somewhat different. Fish oil taken at recommended does not appear to cause increased bleeding even when combined with anticoagulant drugs like warfarin or coumadin. *

Of course, as our mothers told us, we’re all unique little snowflakes. For every person who does not notice increased bleeding, there may be one who does. More on this subject in an older blog.

“Fish oil tends to be less stable than krill oil because krill oil contains astaxanthin.”

This is the over-simplified claim that requires debunking. Science is rarely simple enough to fit on a bumper sticker.

There is no direct evidence to support this statement. All Omega-3 fatty acids and Omega-3 containing oils will oxidize. The molecule form (ethyl ester, free fatty acid, triglyceride, or phospholipid etc.) of the Omega-3 fat influences oxidation. Phospholipids are more prone to oxidation than triglycerides. And krill Omega-3 is in phospholipid form. This suggests the exact opposite, that krill oil will oxidize faster.

In the video’s defense, people think krill oil is more stable because of:

  1. Astaxanthin. Krill contains some astaxanthin. But astaxanthin is notoriously delicate and it degrades very quickly. Milligram quantities quickly become micrograms. In the early days of krill oil, companies used to list astaxanthin levels on their labels. Now, few of them do. Why? Astaxanthin degrades quickly. Barely measurable. This means there is some antioxidant protection provided by astaxanthin when the product is very fresh, but hardly any after a while on the shelves.
  2. Minimal burping involved with krill oil. This is because there is an emulsifying effect provided by the phospholipids in krill oil, so krill oil blends with whatever you’ve eaten and does not float on top of your meal like fish oil might. This makes you not notice the rancidity if/when you burp. More importantly, there is far less Omega-3 in krill oil. Less Omega-3 = less rancidity to be noticed. This does not mean the oil is not rancid. It means you notice less of the rancidity.

So is fish oil less stable?

That depends on many internal and external factors:

  • degree of unsaturation of fatty acids (no difference between fish and krill)
  • how much oxygen the oil has been exposed to
  • light exposure
  • heat exposure
  • UV exposure
  • exposure to metals
  • excessive handling of the oils
  • the antioxidant blend used to protect the Omega-3.

All this has very little to do with whether it is from fish or krill.

Buckle up. It’s going to get a little geeky for a couple of paragraphs.

EPA and DHA, regardless of origin, will oxidize because of the bisallylic carbons between the double bonds. These carbons have low activation energy for hydrogen loss and have a tendency towards free radical formation.

Fish or krill does not matter.

EPA has four bisallylic carbons and DHA five. This is because DHA is a longer molecule and has the potential to oxidize faster/more. Less useful plant Omegas have only 2. Saturated (animal, coconut) and monounsaturated (olive, lard) fats have none, making them much safer from an oxidative stress perspective.

Different oxidation byproducts develop depending on the position of the carbon undergoing oxidation.

As a consumer, you may go to IFOS Consumer Reports and check your product’s rancidity/freshness level.

Acid Value, Peroxide Value, Anisidine Value and TOTOX

You will find Acid value, Peroxide value, Anisidine value and TOTOX listed there.

IFOS Report
Example of IFOS freshness or stability analysis.

Some of these markers are more useful than others.

Acid value is a measure of the amount of fatty acids present in free fatty acid form. In fish and krill oils, Omega-3 is bound to ethyl ester, triglyceride or phospholipid form. When a fatty acid is cleaved, you have free fatty acids. A high measure does not mean the product is rancid – it could mean that some of the Omega-3 is in the free fatty acid form.

The first products of lipid oxidation are measured by Peroxide value (PV). It is considered a leading indicator. The PV of an abused or air-exposed oil will rise over a few months. Then, a cascade of reactions that first produced peroxides isomerizes to conjugated dienes and trienes. These are measured as Anisidine value (AV). For example, EPA produces F3-isoprostanes and DHA produces F4-neuroprostanes.

After a few more months, PV drops off and Anisidine value (AV) begins to climb.

PV tends to increase and then fall while AV will tend to rise steadily over time. So if you look at a super rancid krill oil’s PV without sniffing it or looking at the AV, you might falsely believe that astaxanthin is doing a good job protecting it. Not so.

TOTOX is a calculated value, just like your LDL cholestero.

(2 × PV) + AV = TOTOX.

Generally, any product with a TOTOX higher than 20 should be considered slightly rancid, even though the industry cut off is 26.

Then there’s that sneaky trick, steam deodorization. Here, a somewhat stinky oil is exposed to steam and most of the more polar oxidation compounds are partitioned out with the steam, leaving behind much cleaner oil. It’s a sneaky way to get old oil to resemble new.

Recently a study revealed that several fish oil supplements marketed in New Zealand were severely oxidized. As a consumer, there is no way to tell how rancid your product is without third-party testing services like IFOS.

Of course, nothing beats sniffing and tasting the oil!

My point in going through this detail (besides dredging up the subject of my grad school thesis from 25 years ago and feeling like a geezer) is that it doesn’t matter, not one tiny bit, whether EPA and DHA come from fish or krill. In the absence of astaxanthin, krill oil will oxidize just the same. And astaxanthin is virtually absent in most products.

Krill oil has another issue: it goes from red to brown over time. This is from non-enzymatic browning of the amino acids present and can result in the formation of pyrroles and other volatile (read stinky) compounds.

Krill oil: not more stable than fish oil, just different

Fish and krill oils are both unstable and need to be protected with ultimate care. This means never exposing the oil to air/oxygen and minimizing heat and light.

My beef with krill oil is mostly with the marketing and hype associated with its sale. Krill is primarily a phospholipid supplement…with a tiny little bit of Omega-3 and astaxanthin (if fresh.) Fish oil is just plain Omega-3 and nothing else.

They are not interchangeable in any way. They work differently. They absorb differently and they influence gene expression differently.

Don’t take krill oil because fish oil is ‘less stable.’ Take krill because it is a good source of much needed phospholipids.*

Phospholipids are an essential class of fats that helps cell membranes function properly. Want more phospholipids? Eat egg yolks. Or if Ornish has you scared of yolks, supplement with phosphatidylserine or phosphatidylcholine. Or krill.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.


Join the conversation

  1. Hi Vin – I have been reading about – triglyceride form (TAG) over ethyl ester form. Can you please advice which is better , from absorption perspective. This is being discussed on various forums on the internet including Amazon reviews. There is an article in Amazon which mentions Omegavia 500 switching from ethyl ester to TAG.
    I request you to kindly throw some light on this matter.
    Link :

  2. Hi Vin,
    I’m doing a research on krill oil and fish oil.
    I was interested in your article. It contains very useful information. I would especially like to have more information about oxidation. I want to examine the article you shared so. (Rev. Chem Soc 2010 Nov; 39 (11): 4067-79. Doi: 10.1039 / b922183m. Epub 2010 Jun 9.
    Lipid oxidation and improving the oxidative stability.
    Shahidi F1 Zhong Y.) But I can only get abstract.
    Therefore I ask you to share the entire article from you.
    Thank you for your support,

  3. Thank you for your Wisdom!

    Vin I like a fool took out all of my amalgams without following protocol so ended up getting extremely sick.*( I had vertigo and that’s why I went about this) That was in the spring of 2013. I’m much better now….which still is a process. Thank God I have a brain! Drs were” No Help”. So I had to slowly fix myself and still am.
    My question is because of my mercury poisoning and or toxicity still taken at home in my organs ( brain, thyroid especially) I’m nervous of the mercury in the fish oil and I would assume krill ( I believe they eat phytoplankton..but haven’t researched that in a bit) So still the question…I know I’m in Desperate need of brain help!
    Question ; Should I be concerned with the mercury ?
    Also which have you chosen?
    Thank you

  4. Reading your posts is so informative but I have yet to encounter anything that might relate CHD blood chemistry and deep vein thrombosis.

    After an awful episode last year – I’m 67 – and also pulmonary embolism I was on Xarelto for 7 months. Ultrasound of leg still shows some chronic clot but I got off that medication and take baby aspirin instead.

    One of my motives for doing so was to try some alternatives such as fish oil or cur-cumin to see if their anti-inflammatory properties might help eliminate the remaining clot.

    Three months later the ultrasound was still pretty much unchanged, though I was only taking 3 Nordic arctic cod liver oil capsules for a total of 675 mg omega 3’s – of which EPA was just 225.

    Around that time – Dec 2017 a lipids blood test showed – TC 290, TG 175, HDL 48, ldl 210, vldl 35 and chol/dl of 6.1. I have had high TC > 250 before and tend to run high.

    The fish oil was in triglyceride form and I thought – darn, how is that going to help? Then I switched to krill oil in its original oil state. But I was only doing so to combat inflammation not CHD. This post cleared some misconceptions about both oils and my doses.

    Cardiologist now says I am a ticking time bomb with the LDL. I ordered your EPA 500 thinking more of it now to lower the TG’s.

    I continue to research different plans – and the Fuhrman and Esselstyn (no oil, dairy, meat / fish) plans all seem to share somewhat the same emphasis of yours to eliminate bad carbs – which may be the real rate- determining step.

    I’m now eating oatmeal and beans more regularly – that’s OK, right? both low GI? I have also eliminated all dairy products. I’m more concerned with the LDL & TC than the TG.

    Would you know if EPA could possibly help with the vein condition and whether DVT and CHD share any common ground? All my hematologist tests were negative – thank our creator – and the cause appears self induced – for I worked long hours while sitting for months.

    I’m taking a new lipid test this week and will track results following intake of the Omegavia EPA.

    I appreciate any guidance you could offer on either condition.

    • Hi Frank – the last thing I’d want to hear from my cardiologist was that I was a ticking time bomb! I’m sure that is not comforting.

      Fish oil and Curcumin have not been shown to eliminate blood clots. I worry that the science behind these natural products may not support your intended health effect. That’s not to say that these compounds won’t offer other potent benefits.

      The form of oil (triglyceride form) DOES NOT HAVE ANY EFFECT on your triglyceride levels. The Omega-3 in triglyceride form is simply the SHAPE of the Omega-3 molecule and will not increase your serum triglyceride levels.

      Any effort to manage triglycerides must include three things: vigorous daily exercise, strict elimination of sugar, refined carbohydrates, and flour, along with 3000 mg of Omega-3. Here are a few articles: and As for Omega-3, the effect on triglyceride level depends on the combination of factors above and dose – 3 grams of 3000 mg per day is a good start.

      Anything that increases your blood glucose (like oatmeal) will increase your triglyceride and your risk. Although oat meal is a far safer thing to consume than dry toast and orange jucie! Begin consuming a wide variety of non-starchy vegetables along with generous amount of olive oil. I’d also STRONGLY suggest working concurrently with an Integrative Medicine MD.

      I am not aware of any studies showing EPA’s improvement on deep vein thrombosis. You may want to look into Pycnogenol, there is some promising research with that compound.

      • Hi Frank – I am happy to hear that your experience with taking OmegaVia EPA 500 is positive. The small pill size and enteric coating helps, I’m sure.

        Fake news and contradictory information is not new. It’s just only recently that it has been politically and socially weaponized. We’ve had bad science floating around as good for a long time. The link you mention that suggests only DHA influences triglycerides is simply bad science. The study has several flaws: 1) it was too small 2) the study concluded that DHA is no better than EPA 3) different arms of the study received different amounts of Omega-3 (!!) and 4) the study was funded by a DHA producer. I know the current batch of editors at Nutraingredients and they’d never publish a piece with that headline today.

        The truth is that both EPA and DHA are good at maintaining triglyceride levels when combined with a healthy diet and exercise plan. The differences in efficacy may be a couple of percent one way or the other, with a very minor advantage to EPA because of its other health properties that are so critical for heart health.

        As for Dr. Fuhrman, I strongly agree with him on the following: 1) reduce sugar 2) reduce processed seed oils, 3) eat more vegetables and 4) eat less refined grains (flour). That’s based on facts and published science. My nutritional outlook parts ways with Fuhrman on all other subjects. But I have no clue where he got the data on 3 grams of fish oil being harmful or how the GI tract is overwhelmed. There is no evidence whatsoever to prove that. If you follow Fuhrman and find success, it is likely because of the critical 4 dietary corrections (above) that he suggests. Virtually every successful dietary intervention or diet book has variations of these 4 key changes. Fuhrman to Paleo to South Beach to New Atkins to whatever comes next.

        As for salmon, yes, you can’t go wrong with wild-caught salmon 2 or 3 times a week. But that alone won’t provide you with ‘interventional’ levels of Omega-3 if your diet is high in sugar and refined carbs and/or if you are exercise-deficient.

  5. Is egg of fish good for health.
    What is the right quantity of Astaxanthin?
    How much Krill Oil should be taken? It generally has lower levels of DHA/EPA.
    With what foods should fish oil be taken to increase bio availability.
    Does ingesting Phosolipids through Krill oil make the cell walls soft and flexible and hence more permeable.
    My HDL:56;;TGI:60;;LDL:133: TOTAL Cholesterol :201,,VLDL:12,,,LDL/HDL:2.38,,,CHOL/HDL:3.59

    • Hi Roshan – eggs and fish are good for health. Eggs of fish are great too – they are very high in DHA and other nutrients.

      Astaxanthin is not an essential nutrient, but a few studies have shown health benefits at 6 to 8 mg per day. I don’t recommend krill oil as an exclusive source of Omega-3s due to the low EPA/DHA content and high cost. However, 500 mg of krill oil could provide a good source of phospholipids, which provide other health benefits.

      Taking fish oil with any meal will help absorption.

  6. Hi Vin, love reading your articles. Question…. I see these new products out now that are Omega 3 in liquid bottles (NutraSea, Webber Naturals etc) and they contain 4.55g of fish oil with EPA 750mg, DHA 500mg, for a total of 1250mg. How is this in comparison to a Krill Oil (neptune) that is 1000mg but only 120mg EPA and 70mg DHA and says total 230mg Omega 3. The Omega 3 is always lower in krill oil but from what I understand its how its absorbed… so would the liquid Omega 3 1250mg be best option? And if I want it for cholesterol/triglycerides and need 3000-4000mg omega 3 to see benefits I would need take 3x dose, but that’s then 4.55mg fish oil x 3 which is 13.65g total! Isnt that alot of fish oil? Is there an upper limit? Reason I also ask is these liquid bottles of omega 3 in these high doses are most affordable compared to pills… wanting to find best and most affordable way to get 3000mg omegas 3…. Thanks Vin….

    • Hi Jeff – liquid Omega-3 products are quite old actually. It’s not that different from the cod liver oils our grandparents had to choke down. The items you mention are good, but fairly low in Omega-3 potency. You should be able to find products with 2000 to 3000 mg of Omega-3 per teaspoon – look for those. That’s where you’ll find value. You’d have to take an awful lot of teaspoons of the brands you mention to get 3000 mg of Omega-3.

      With most liquids, even though they look good on paper, taste and controlling rancidity become factors. Keep them refrigerated and consume within a month or two of opening.

      Krill oil and liquid fish oils are completely different things. Krill is really a phospholipid supplement with a hint of Omega-3. Fish oils are Omega-3 supplement with little or no phospholipids. Don’t compare them. The tiny bit of Omega-3 in krill is well absorbed, no doubt. But you’d need a lot of krill to get your Omega-3 index up and above 8-12%.

  7. Hello Vin,
    First off, Amazing products and contribution to bettering the health of society.
    Sadly though, I live in a country where accessing your products is extremely hard and costs two times or more to source it.
    Thus, have to resort to local Ethyl Ester form Fish oils till some ally visits the States.
    My question is, is there a way to convert the ethyl ester form fish oil to triglyceride at home using chemicals and processes?

    • Hi Harsh – first, try buying through They ship to wherever you may be. I would not bother converting from ethyl ester to triglyceride. It’s absolutely not worth the hassle. Whatever horrible thing you may have heard about ethyl ester is wildly exaggerated and so is the superiority of triglyceride. Yes, TG is slightly better absorbed if taken on an empty stomach. But that minor advantage is certainly not worth setting up a small enzymatic conversion unit in your garage or kitchen!

  8. Hi Vin, not sure you can help me out here. I know a granny who is suffering from dementia. She can’t remember recent things and is slowly forgetting the past as well.
    Thought of omega 3 as a supplement for her but are there more things or stronger stuffs that can help her pls?

    • Hi Ken – while Omega-3, especially DHA, is critical for brain health and function, we do not have sufficient evidence to suggest taking Omega-3 as a preventive or cure for dementia.

      There are some pharmaceutical medications that are reasonably effective at slowing the progress of dementia, but I don’t know any nutrient that has the same effect.

  9. Vin, hi! Thanks for your awesome blog in general and this article in particular!

    I’d like to ask your expert opinion on fish/krill oil supplements for the APOE3/4 variation. I’ve learned that one of the problems with this SNP is that the transportation of the TG & EE forms of DHA through the blood-brain barrier is severely compromised.

    So I probably have to either increase the total amount of DHA I consume or to have it partially in the PL form.

    I understand that the best source for the PL-form DHA would be caviar – but that’s not an option for me – I can’t stand the taste.

    I’ve also read that fish by itself contains only about 1-1,5% of it’s DHA in the PL form – so it’s probably also not an option.

    This (as far as I understand) leaves me with 2 possible strategies: either to consume more DHA in TG form (for example consume 3 of your DHA-600 and 1 EPA-500 softgels daily) or to combine fish oil with krill oil.

    What would you suggest? How much DHA/EPA would you recommend to take daily in TG form (from fish) and PL form (from krill)?

    • Hi Tim – yes, individuals carrying the APOE4 allele struggle (a little) to incorporate DHA into the brain if it is in the EE or TG forms. For these individuals, the phospholipid (PL) form of DHA is best. You can get that from krill oil or fish oil sold in the PL form.

      The only issue with supplements in the PL form is that there is very little DHA in each pill. You would have to consume 10-20 krill oil pills a day to get a clinically meaningful dose of DHA.

      Your options (if you hate caviar) is to combine TG form of DHA at a higher dose, consume fish regularly, and take some krill oil supplements along with the above.

      I don’t have clear guidance about how many mg of TG form DHA to take to equal a meaningful level of DHA in PL form. Sorry. If I were to guess, I’d suggest 3 or 4 times as much DHA in TG form, with the assumption that persons with APOE4 allele absorb about a quarter as much as those without the allele. That is an educated guess and it is not based on published evidence.

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