The Definitive Guide to Fish Oils

I was actually a little surprised that we hadn’t already done a Definitive Guide to fish oil when a Worker Bee suggested it to me. We’ve mentioned it enough, and it’s a hot enough topic that I just assumed we’d done a big comprehensive guide to the stuff. But, as my staff so eagerly likes to inform me, I was completely, utterly wrong (enjoy it now, cause it won’t happen again anytime soon!).

A quick look at the archives revealed that we actually had compiled enough content to make a Definitive Guide – we just had it spread out over several wide-ranging posts from various dates. But that’s not to suggest the following is just a rehash of old content. Rather, I’ve pulled it all up, cobbled it all together, and topped it with some entirely new stuff. The result, I think, should be pretty definitive.

Why Fish Oil?

Okay. Everyone – even peddlers of Conventional Wisdom, low-fat proponents like Dean Ornish, and certain vegetarians – agrees that getting enough fish-based Omega-3 fatty acids in our diets is good for us. In fact, the importance of dietary fish oil just might be the only point where I don’t butt heads with, well, almost everyone else. Still, though recommending a fish oil supplement is generally safe for anyone, it’s important to understand why fish oil is so beneficial. So why should we take it as part of a Primal lifestyle?

It all comes down to Omega-6/3 balance. You can’t talk about fish oil without getting into Omega-3 fatty acids, and discussing Omega-3 fatty acids is useless without understanding their relation to the Omega-6s. We’ve mentioned this relationship multiple times before, but I’ll reiterate: a 1:1 Omega-6::Omega-3 dietary ratio helps keep dangerous inflammation in check. Seeing as how most Omega-6 fatty acids can be found in “vegetable” oils (soybean, corn, peanut, sunflower – to only name a few), fake butter products, grain-fed animal fat, and other modern contrivances, it is understood that Grok rarely encountered them – especially not in the excessive levels most people see today. He was munching on nuts and seeds, sure,  and those have moderate amounts of Omega-6s, but he certainly wasn’t setting up processing plants to press wild maize for the Omega-6 rich oil. Simply put, Grok would have gotten plenty of Omega-3 fatty acids from seafood, wild game, and wild vegetation, with minimal amounts of Omega-6s, enough to give him a 1:1 ratio. On the other hand, the Omega-6 to Omega-3 ratio of the Standard American Diet, replete with fake fats, processed vegetable oils, and grain-fed meat, is said to approach 30:1!

To understand why that imbalance is so harmful, you have to understand eicosanoids. Polyunsaturated fats (which include Omega-3s, like fish oil, and Omega-6s) convert to eicosanoids in the body. Both Omega-6 and Omega-3-derived eicosanoids are important signaling molecules, but each has different effects, both figuring prominently in the body’s response to inflammation. Omega-6 eicosanoids are pro-inflammatory, while Omega-3 eicosanoids are less inflammatory. Omega-3 eicosanoids (the type we get from taking fish oil or eating fatty fish) actually reduce inflammation; in an unbalanced diet heavy in vegetable oils, the Omega-6 eicosanoids far outnumber the Omega-3s and contribute to a lot more inflammation.

As Stephan explains here, there is an intermediary step in the process of conversion from fatty acids to eicosanoids: highly unsaturated fatty acid (HUFA) conversion. Dietary PUFAs are converted into HUFA, which is then stored in cell membranes. When a cell requires eicosanoids, it uses the HUFA stored in the membrane to form them. Here’s the catch, though: the cell doesn’t distinguish between Omega-6 or Omega-3 HUFA for eicosanoid conversion. Whatever’s available in the membrane is what they’ll be using, Omega-3:Omega-6 ratio be damned. And, as Stephan says, “the proportion of omega-6- to omega-3-derived eicosanoids is proportional to dietary intake.”

Ratio matters, big time, and it may take a while before the effects of establishing the O6-O3 dietary balance are visible in your tissue, because you’ve still got to clear out the residual unbalanced HUFA in your cell membranes. But once you do, you’re good to go – just check out the heart health of populations with good HUFA ratios. If data were available, I bet you’d see Grok measure up pretty favorably on that same graph.

So yes, maintaining a balanced Omega-6 to Omega-3 dietary and HUFA ratio is the main reason for supplementing with fish oil, but there are still other benefits. Even if you’ve successfully cut out all vegetable oils and fake butter spreads in favor of grass-fed meat and real fats, there are still a couple reasons – other than for cardiovascular health – for you to supplement with fish oil: the EPA and DHA fatty acids it contains.

Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) play big roles in the formation of brain and retinal tissue. Huge concentrations of DHA can be found in fetal brain and neural development, especially during the last trimester. Babies, especially those yet to be born, can really benefit from fish oil supplementation. Kinda makes all those calls for pregnant women to avoid fish seem a little misguided, eh? DHA/EPA might also be a boon to the elderly; as we age, cognitive and visual health becomes more important than ever, and low DHA/EPA levels may contribute to the onset of Alzheimer’s disease, other dementias, and vision problems. There’s also been some research suggesting DHA/EPA has some beneficial effect on the risk of various cancers, including prostate, breast, and colorectal. Suicidal depression and schizophrenia, too, may be linked with low levels of essential fatty acids like EPA and DHA. And finally, fish oil supplementation may even help improve insulin sensitivity. Or, you can just check out this comprehensive look at fish oil and chronic disease. Whew! Essential fatty acids, indeed.

If you’re interested in the approximate levels of EPA/DHA in various foods, check out the table in a previous MDA post.

Any Downsides?

Hmmm. Less inflammation, lower heart disease risk, better vision, more neural development, less cancer risk, proven health benefits: what’s stopping us from guzzling gallons of delicious fish oil? Well, the old adage about “too much of a good thing” comes to mind, because there are some caveats.

As stated before, the most important reason to supplement with fish oil is to restore the Omega-3/Omega-6 balance in your diet and promote good heart health. Not all of us have access to grass-fed or wild game, or wild-caught fish, and taking fish oil supplements can be an easy, healthy way to counteract the Omega-6 PUFAs in our lives. But for those of us who eat exactly like Grok and have next to no Omega-6s in our diet, fish oil isn’t as crucial. In fact, taking in more than three grams of fish oil may lead to adverse levels of blood thinning (as it hasn’t actually been observed, don’t worry too much about this one, especially if you’re eating tons of Omega 6, because you need all the fish oil you can get!). And don’t forget that, being a fairly unstable PUFA, fish oil can still be oxidized and contribute to inflammation. In its pure, stable state, fish oil protects the heart and fights inflammation, but oxidized fish oil can still be harmful. To avoid oxidized fish oil, only buy it from reputable sources, test your capsules for rancidity by biting into one, and keep them refrigerated (or at least out of warm areas). Don’t overcook your fatty fish, and don’t cook with fish oil (one study showed a huge drop off in EPA and DHA levels when heated).

A high carb/sugar intake might also make fish oil supplementation a bit risky. As long as you’re keeping dietary sugar and refined carbs low (which, you know, should already be happening), fish oil is a great supplement. But, as Peter of Hyperlipid cautions, diets high in sucrose or alcohol can increase the load on your liver when paired with high dose fish oil supplementation. I know I’m preaching to the choir here, but if you’re taking decent amounts of fish oil every day, watch your sugar and alcohol intake to avoid any liver complications. Though it may not apply to MDA readers, I’m sure you know someone who fits the bill.

Different Sources

Does it matter how you get your fish oil? As long as it’s from a company you trust, and it hasn’t turned rancid (check the expiration dates), you should be fine. Some people like taking bottled fish oil by the spoonful, but some may have trouble with the oily sensation (not to mention the taste of some of those brands!) in their mouths. Cod liver oil is another option; while it’s slightly lower in DHA/EPA levels, it does contain Vitamins D and A. If you’re looking to get more of those vitamins in your diet, cod liver oil might work for you. Most people, however, go for the capsules. They are by far the most convenient (you can easily pop ‘em in your mouth on the go), and those who can’t stand the taste or sensation of actual fish oil can still get the benefits by taking the capsules. Just beware of cheaper brands – while they may be easier on the wallet, they’re also prone to going rancid and causing lethal fish burps.

What It All Means

Unless you’re eating fatty fish every day, following the Primal Blueprint means you’re a prime candidate for fish oil supplementation. See, the typical MDA reader has a low sugar intake, avoids refined carbs, but is often faced with the prospect of eating less than ideal meat and animal fat. We all wish we could dine on wild venison and fresh caught salmon every day, but most of us just can’t. In cases like these (which is the majority of us trying to eat and live right by Grok’s ways), taking 1-3 grams of fish oil each day is a good way to restore the fatty acid balance in our cells, promote good heart health, provide essential fatty acids for our brains, improve protein synthesis after workouts, and counteract some of the downfalls of modern life.

Read my follow-up post to the Definitive Guide to Fish Oils in which I answer some of your most pressing fish oil questions.

Prefer listening to reading? Get an audio recording of this blog post, and subscribe to the Primal Blueprint Podcast on iTunes for instant access to all past, present and future episodes here.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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132 thoughts on “The Definitive Guide to Fish Oils”

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  1. Typo: should the 30:1 in last sentence of paragraph 4 be be 1:30 as you define the ratio Omega-3:Omega-6 in that same paragraph? And your point was the average American diet has way too much Omega-6.

      1. Does the oil in fish such as salmon/sardines go rancid once heated and cooked? It seems many recommend baking or broiling fish to protect nutrients, but how does baking or broiling not damage the unstable oil that fish contains?

  2. Fish oil is such a great and easy way to increase our omega-3 fatty acid consumption, especially for people who don’t eat grass fed and free range animal products.

    However, fish oil is still much more processed than meat, vegetables, and other “paleo” foods. As such, there’s always risk of contamination from either processing procedures, additives, or a poor quality source of fish.

    I personally use Carlson’s and think it’s a reputable brand. What does everyone else use?

    1. I found a relatively cheap, but high quality brand, Nutratec Life Sciences sells “Life Support Omega-3”. 40$ for a bottle of 150 1g capsules with a 40% EPA content and 20% DHA content. They’re also IFOS independently certified, so that’s an extra bonus. This is the best deal I’ve found yet.

      1. I use MX Omega 3, quite impressed with the purity of fish oil supplements from, sourced from sub Antarctic Oceans!

      2. guys, check out purepharma fishoil, best stuff in the market you can get!!

    2. I like carlson’s too, the liquid. It seems to me to be the form I most benefit from–I can’t say why it would be any different from a capsule, but I feel better so I stick with it. & cost-wise it’s on a par with other good brands, maybe even a little cheaper, if you keep your eyes peeled and buy it on sale.

    3. I just started taking Carlson’s fish oil. Do you take 2 a day since it is only 500mg of EPA/DHA?

    4. i eat a teaspoon of cod liver every day. and I don’t mean cod liver oil, but cod liver itself, the real stuff. in brine (or it’s own oil) of course. especially in wintertime it really helps me to get my megadose of D and A vitamins, not to mention the Omega 3’s.

    5. My favorite is Innate Choice. No mercury, no contamination and proper ratios as found in actual fish and not concentrated.

    6. My wife’s always asking me to order these Omega 3 supplement sold by Vision Group. That is to lower down her cholesterol level and supplement for muscle cramps during work out. I personally liked em with the natural lemon flavor at 800mg EPA and 600mg DHA 2 soft gel caps a day, very good alternative for inflamed joints…

  3. You recommend storing fish oil in the fridge, but how about storing capsules in the freezer? Wouldn’t this be an even better step to take to prevent the oil from oxidizing?

    I’m glad you did a primer on fish oil, I’ve been thinking about it lately. But I would have liked info on DHA/EPA ratios and quantities. I have know idea what is a typical or ideal DHA/EPA ratio or how many mg of each I should be taking.

    1. …And with what Vin was saying, I would be more comfortable consuming fish oil from a reputable source. I see fish oil at the supermarket but am skeptical if the supermarket provides quality fish oil.

      1. I’d be remiss if I didn’t mention my own fish oils. As detailed above, I wholeheartedly believe the research supports that fish oils are an important part of a healthy lifestyle. And I wanted the absolute best so I went out and made my own prescription grade fish oils. I think they’re so important that I even give them away for free to my Master Formula customers (since the Master Formula is designed to be the be all and end all for your daily high-antioxidant supplementation). I know, I know. Enough of me raving about my own wares. 😉 Take a look though – – and if you have any questions feel free to drop me a line: [email protected]

  4. Nordic Naturals has great fish oil. A little more expensive, but you only need one teaspoon a day, better than 5-8 pills!

  5. Very interesting post, I was actually looking this morning into the importance of omega ratios (how’s that for a coincidence). One question I have is this, should one’s intake of supplementary fish oil be adjusted based on the intake of the omega 6 heavy foods or will our bodies just dispose of excess of both once it reaches it’s preferred ratio? And if so is there a “rule of thumb” that would make it easier to get this ratio down?

    1. Well, a good rule of thumb is to fix the ratio by decreasing omega-6, rather than increasing omega-3. The less vegetable oil you consume, the better off you are, and you won’t have to worry as much about eating an artificially high amount of omega-3. Of course, a primal-type diet pretty much takes care of that for you…

      1. I eat about 80% primal (i allow a bit of sway for protein supplements and cheeses/creams), but I was wanting to go over my diet and figure out how much I need to supplement given the amount of red meat I eat, if i could eat salmon for half my meals I most certainly would but in my current situation I’m stuck with beef compromising at least 70% of my total meat intake followed by chicken and what fish I can get in there.

  6. I take high-vitamin D cod liver oil off the spoon every day. It goes down alright… But it’s worth it.

    I’m not sure if it’s all in my head or a coincidence, but once I started taking CLO, my sex drive went through the roof. There were times when I seriously started thinking about humping a fire hydrant… I’m a 30 year old male, eat a WAP/primal diet (mostly meat, eggs, veggies, fruit, fermented or raw dairy, and sprouted or fermented grains). My libido wasn’t low, but the CLO (at least I think it was the CLO) really kicked it up a notch.

  7. I take in about 6.4 grams EPA/DHA of fish oils. Do you think this is bad or overkill? Ive never experienced anything bad (not that I might) and its been close to a year since I upped my dosage.

  8. I’m thinking about doing a follow up post to address any questions you may have. There have already been some good ones. Keep ’em coming!

  9. Is it worth noting that too much fish oil supplementation can increase bruising?

    I know that with the blood thinning properties, I tell my friends, when they start a fish oil supplementation, to watch for increased bruising. If you appear to have a significant increase in bruises (specifically of unknown origin), then experiment with lowering the daily dosage.

  10. I was so glad when Mark came out with Damage Control Vital Omegas. I take them and they truly are the very best!!!! Also, just as Master Formula is, Vital Omegas are easy on even sensitive stomachs, they will not cause stomach upset,just be sure to take it with food.
    I don’t know about you, but i just can not swallow flax oil, taking Vital Omegas does not have that fishy smell at all. All of Mark’s products are perfecctly balanced, Vital Omeagas is the way to go when it comes to taking fish oils, THEY ARE TOP OF THE LINE!!!! Check it out on The Store Tab under Mark’s Pic.
    To everyone, hope you’re having a great day!

      1. No, i don’t work for Mark, i’ve never even met him. I like to rave about Mark’s Products because i take his Master Formula and Vital Omegas and i’ve never felt better in my life. I always encourage everyone to give his supplements a try because i’d like for everyone to experience how healthy they can feel as I do. I’ve tried so many vitamins in my life and nothing comes close to Master Formula and Vital Omegas, like i say, i hate the taste of Flax Oil and gives me a yuky feeling-Vital Omegas is easy to take and makes me feel better. I’m a big believer in Mark’s products just because of how his supplements turned my health around like i could of never imagined, i feel healthy with a higher energy level. NO other supplement has ever done all this for me. Master Formula is the “best”, ALL of his products are!!!!

  11. I’m surprised you don’t hear much mainstream media coverage about your eicosanoids and keeping your eicosanoids factory in check – since they have their microscopic little hands in, well, just about everything that keeps up humming along properly (or with an imbalance, quite improperly). New flash at 11 – the silent killers making you sick from the inside out! Heh, just kidding.

    I like to buy the “flavored” liquid fish oil (Carlson’s all the way!) and keep it in the fridge, it saves me from having to bite into a capsule every week or so, and I can’t ever “accidentally” take in any rancid fish oil… cause when the liquid stuff goes – you’ll KNOW! 🙂

    Follow-up Question:

    What is the concentration of DHA/EPA (generally) in say.. Sardines (canned in sardine oil, not olive oil)? I’m just wondering if eating sardines would be “just as good” as fish oil supplements, or would it be too weak to replace them.

  12. Great write-up Mark!

    The only thing I’d like to add is that if you take a lot of fish oil and are susceptible to bleeding (like nosebleeds), those occurrences may increase. I think there’s also a higher occurrence of hemorrhages in Eskimos who have extremely high fish diets.

  13. I eat 100% grass fed Black Angus beef, 0% vegetable oil, (I use coconut and EV olive oil) no processed foods whatsoever, and no sugar at all. I do take Krill oil daily because, well everyone says you need it. But with my diet, do I really need it?What happens if my ratio is 2:1 in favor of Omega 3?

  14. Mark,

    I’m really glad you finally did a post in regards to fish oils. You always have a well thought out explanation of a miriad of helath tops that are always interesting to me. I read your blog almost everyday. To date, most of what i know in regards of fish oils I have read from Barry Sears. Who places a lot of emphasis on only only consuming the pharmaceutical grade omega 3. The reasoning being;Altohugh these are considerably more expensive, the purification method decreases the contamination of heavy metals and results in an increased concentration of EPA and DHA per capsule. Thus leveling out the cost per pill compared to an unrefined brand when comparing price : concentration DHA and EPA ratio. I honestly have never considered rancidity to date, but its a really good point.

    Could you possibly comment on the various sources and grades of fish oil/ omega 3 supplements.



    1. Jeanine,

      Just about all reputable fish oil capsule manufacturers use the very highly refined (purified) oils these days. There is little chance of contamination from any of these, so Barry’s advice is a little outdated. There are some pharmaceutical companies that think so highly of fish oil that they are trying to idolate the EPA and DHA even further (so they can charge four times as much for prescription fish oil). That’s a case of Big Pharma seeing that nature does it best…but still trying to carve out a protected market.

      As for rancidity, most fish oil caps (soft gelatin capsules) have vitamin E added as an antioxidant. Between that and the sealing of the capsules and bottles, the oil is stable for two or three years at room temperature. Our Vital Omegas are stored at a temperature-and humidity-controlled warehouse until shipping. I keep mine in the fridge to be cautious, but unless your room temp regularly exceeds 75 or 80, RT should be fine for a month or two at a time.

  15. Definitely take Mark’s Vital Omegas! I take my 3 capsules every day and I have absolutley noticed a huge difference in my health (especially since I take his Master Formula daily as well). They are so easy to swallow and no fish burp. Top quality!
    (Mark- I’ll make a shameless plug for you!!)

  16. Has anyone tried Biotest Flameout?

    I think it’s considered more of a “designer” fish oil because it has some other things in it such as CLA.

    I never see it reviewed with other brands like Nordic Natural and I’m not sure if I trust all the hype on the t-nation website.

    Any thoughts?

  17. Has anyone used the Coromega fish oil supplements? They come in a squeeze packet and are supposed to be high quality. Is there any reason why they wouldn’t be a good choice?


  18. Mark,

    I love this post. I have been taking fish oil supplements for a little while, and i was about to stop taking them just because i wasnt sure of the negative affects. Also, I ordered your book last week and I’ve been checking the mail everyday awaiting its arrival. Keep up the good work.

  19. I’ve heard that the recommended amount of fish oil you should take is 0.5 grams for every ten lbs you weigh. That means for someone that weighs 170 lbs, they should take 8.5 grams a day. Is this too much?

    1. Will, 8.5 grams is a lot IMHO. Also depends. If you have reduced your O6 consumption (little or no vegetable/grain/seed oil and choosing grassfed meats) then you needn’t supplement that much. If your O6 is high, 8.5 grams might be spot on. Also depends on the % DHA EPA and triglyderide content of the oils you are taking

  20. I’ve read that krill oil, although more expensive, is more potent than regular fish oil. Any recommendations about a mixed dosage of krill and fish oil?

    For some reason krill oil isn’t supposed to be refrigerated. Any idea why?

  21. Very definitive guide. Thanks!

    Just be careful when traveling or an over-zealous airport security person might confiscate your fish oil capsules. I had a jar of about 300 capsules taken away from me in New Zealand not because of any quarantine violation but because she deemed it a security threat! Well the label did say Gel-Caps.

  22. Mark,

    Just linked over to your PBP book Web site for the first time.
    Kind of amusing to see the “mass market” version of your stuff (bold yellow highlights, supermodels, and all :-)).
    Good luck!!

    1. Thanks, jimmydeeee! I appreciate the link.

      Yeah, I want to very clear about what readers can expect. Many people are brand new to the Primal Blueprint concept. The general audience that views is different than the strong community of existing PBers here at MDA, so I had to take that into consideration. The goal is to get this message out there and to change lives. I’m doing everything in my power to do so. I always appreciate a helping hand! Thanks again!

  23. Actually, I know of one documented case of a child having coagulation problems (severe enough for hospital admission) due to excess fish oil supplementation. As for adults, I know there are bodybuilders taking fish oil gelcaps by the handful (I saw one recommendation for 6g/day!) but I have no idea what side effects if any those folks might be seeing.

    1. It can also cause you to bleed without stopping because of the thinning of the blood…not good.

      If you bleed profusely when you shave then you need to cut back.

  24. Can I get the same benefits from Flax oil? If not, what’s the difference?

    Will you recommend a few brands of fish oil to try?

    1. Flax is ALA not DHA and EPA, the body converts very little ALA to DHA and EPA and you aren’t getting the bang for what you are paying for.

      Better to eat freshly ground flax for the lignans, protein and fiber.

  25. Is there such a thing as too much fish oil? What if the normal 30:1, omega 6 to omega 3, was potentially reversed? What would the implication of a 1:2, or possibly higher omega 3 ratio be?

    I have always wondered about this because it is hard to keep exact detail of your ratio. I actually don’t have a clue how you would even start to keep a mild track of your ratio since nutrition profiles can vary so much.

  26. Krill Oil and Coated Fish Oil Capsules

    Paula, I too would like some more info on Krill oil. Better? The same? Worse than fish oil?

    Mark, I see eneric (not sure of spelling) coatings on some fish oils. I’ve heard this is so it won’t dissolve until it gets in the intestine which in turn means no fish burps. Is this accurate? Does it matter? Are yours coated?

    Thanks for the great topic. Oh, I like the book too! Not sure how many you signed before mine but the signature still looked good. Grok On!

    1. I read somewhere that eneric (enteric? something like that) coatings are used on inferior fish oil supplements because the rancid oils will cause fish burp. I use Nordic Naturals Ultimate Omega soft gels and have never had a fish burp. I have been taking Nordic Naturals since 2010 with no problem.

  27. As always, a great article Mark. I have been buying a NZ brand fish oil that is bottled in smaller batches (90tabs) and I have really noticed the difference from using that opposed to the bulk containers of 500 in the supermarket/health food shop, it is worth spending the extra money.

  28. Something about buying fish oil just goes against the grain for me. I’d just rather eat fish 1-2 days a week and get it that way. Same for walnuts. Just need to make sure I avoid having too much to avoid the whole mercury issue, right?

    1. I doubt eating fish 1 or 2 days a week and snacking on walnuts is going to replace fish oil supplementation.

      Fish oil is more about balancing. I could be wrong but I highly doubt 1-2 servings of fish has enough omega 3 to balance out other areas of your diet that may be lacking. Especially if it isn’t wild caught.

      If you only eat grass-fed grass-finished meats and other equally naturally nutritious animal products, then fish oil might not be a big deal. But if you eat any form of conventional meat and/or animal products. I highly doubt the already balanced fish is going to have enough omega 3 to makeup for the rest of your diet.

  29. Is there any proof that this stuff works? Your article is written just like any other supplement promoting article, so it sounds a little fishy to me…

        1. Thanks for the response. Here’s what I found in the third result of your google search:

          “Clinical studies[4][96][97][98] indicate that the ingested ratio of n?6 to n?3 (especially Linoleic vs Alpha Linolenic) fatty acids is important to maintaining cardiovascular health. However, two studies[99][100] published in 2005 and 2007, found no such correlations in humans.”

          On top of that, the “benefits” of fish oil are typical of ANY supplement, or any natural food for that matter (even acai). Whilst there are many case studies of fish oil use claiming that these benefits are true, there is no factual data claiming definite benefits. Like usual, the most common words in their studies are “may”, “might”, “can”, “could” and “should”. These words imply that it may work, but likely wont, because there is not enough proof to say that it definitely DOES.

          Furthermore, with studies claiming that fish oil does not work, and studies proving there to be side effects that counter the benefits, are you really willing to and add this food to your diet permanently?

          If you were to take every supplement that is recommended by “health professionals” with the same benefits as fish oil, you’d be popping 50 pills a day and spending a hundred bucks a week on supplements alone.

          I’m willing to bet that the people on Earth who have lived to 100 years or more did not live off pills and prescriptions, they just ate a well balanced diet of real food. **

          However, I’m always open to discussion and if you can help me find proof that fish oil really, definitely does improve health more than every other supplement on the market that claims the same things, I’ll be a true believer and help spread the word.

          I’m the atheist of fish oil. lol

          That Best Life Online article is very well written, but they’re trying to tell us that humans didn’t advance and become civilized because of a lack of food or a change in environment, they’re saying it all happened because they discovered fish.

          The author has been taking it for one month as of writing the article, and claimed that the noticeable benefit was that they could think clearer and faster. They then continued to say that they’re also eating healthier overall. So perhaps the effect is not because of the fish oil, but the overall improvement in their diet.

          Either way, I’m going to test it out myself and see if I notice a difference after one month. Usually the effect will be noticeable once I stop taking it, so it will most likely be more than one month before I can report on this.

          ** While I’m doing this, if you know any 100 year olds, ask them what their diet has been like throughout their life, and see if they take fish oil or eat fish 2 times a week.

  30. Miriam, what is the brand you are buying in NZ? I’m taking krill at the moment but would be interested in finding a good fish oil too…without the fishy burps which is why I changed to Krill.

    1. I got rid of the fishy burp problem by taking my caps at the beginning of my meals.

      1. Fish burps are caused by rancid, inferior fish oil. Please look into a high quality brand like Nordic Naturals.

    1. Yeah the exchange rate isn’t too pretty and I too have to eat LOL Thanks Miriam 🙂

  31. Great Post.

    Just to add a little humor:

    From what we have learned from smart people like Mark and Stephan, it does not surprise me in the least that some snakes would be high in EPA as reported here:

    Why did I think to google this topic? just look at all the remedies of the past that have turned out to be true? Grandma was right, cod liver oil everyday IS good for you. What other traditions and folk medicines of the past have we forgotten or dismissed as foolish?

    Maybe an apple a day does keep the doctor away (certainly an MDApple), maybe chicken soup does cure a cold (bone marrow), maybe even snake oil had it’s benefits.


  32. Sorta out of topic, Mark, but it still does talk about healthy fats. Redundant considering how much has been said over here about it, but I thought you’d wanna see it anyway:

    Butter V.S. Marge —

    1. I mean, what will it taste like if it is rancid? If it is good it will taste like fish?

  33. I think some people are worrying too much about overdosing, if you’re taking 6 capsules it’s only the equivalent of 6g of dietary fat, less than a nice salmon steak!

    I’ve yet to see any independant evidence for Krill Oil so the only benefit I can see to it is that it has a lower environmental impact.

    1. I read some studies stating that more than 5 grams of omega 3 “can” cause inflammatory illnesses. As with everything, overdosing is bad.

      It sounds to me like fish oil is just one of those foods that should only be required if you have a deficiency in the omegas. A well rounded diet should have enough of the omegas anyway I would think..

      Here’s a GREAT website on it.

      Plenty of FORS and AGAINSTS.

      1. Agree with you. Too much of a good thing can definitely turn into a bad thing. Everything in moderation, including omega-3s.

        Looks like that National Institute of Health reference is now a dead link. Too bad, usually NIH articles are well put together.

        Here’s another fish oil resource that’s pretty in-depth:

        They list similar pros and cons, as benefits and risks, and include an important section on interactions.

  34. Mark, Is there any way to measure your Omega 6/Omega 3 ratio? That would help someone know just how out of whack things were.

  35. I eat almost nothing but grass fed beef, lamb, wild salmon, sardines, walnuts, almonds, eggs and green leafy vegetables. Would fish oil help me? Perhaps I already get more Omega 3 than 6. Would Grok have taken supplements?

    1. Grok wouldn’t have had supplements to take….but Grok wouldn’t need them as s/he, depending on geographic location, likely ate fish. 🙂 WE, however, do not live 10,000 years ago and can’t just go pluck a fish out of the ocean/stream. But, we can stay as close to real fish as possible and go with a wild salmon supplement, minimally processed, no heat, natural triglyceride form. Thoughts?

  36. Would Grok take supplement?

    Throughout history there have been practitioners of herbal medicine so when Grok felt sick I’m sure he had knew what to eat to make him feel better, or at least knew someone who knew.

    Would Grok take daily supplements? When Grok found a herb that he knew was particularly good, did he eat it all in one go? Nah. Did he take some with him for tomorrow? Did he return daily for more. Sure why not!

    I think however, that moderns attempts to isolate the ultimate compound for health and package it in a easy to swallow package is futile. In the end our bodies need food, whole food with all the good stuff in it in the right balance. Since we live now in a time when our balance is our of whack it is probably smart to supplement the balance with sensible isolated compounds.

    Vit D, Omeaga 3 (maybe K2) seem to be on the top of the list at the moment with our current understanding of the human body, food supply, lifestyle

  37. I take 30ml of Melrose Cod Liver Oil daily. To avoid the taste I make up a drinking yoghurt and CLO mix:3 Tablespoons of plain (Greek Style) yoghurt in a mug of water with the 30ml of CLO. No fishy taste and the dairy is fermented. (OK, not strictly Grok but OK according to ‘Nourishing Traditions’; my food bible until Primal Blueprint.

    I also have a second mixture each day: 30ml of Apple Cider Vinegar, 1 teaspoon of raw honey, 1 teasoon of tumeric; with 2 teaspoons of crushed garlic, one teaspoon of crushed chilli and one teaspoon of crushed ginger (with warm water) followed by a raw tomato.

    All up about one-third of daily energy requirements.

    I am finding it difficult to obtain grass-fed meat as all the butchers proudly proclaim that their meat is grain-fed so my Omega 6 levels could be a tad high.

  38. Snake Oil

    The references to snake oil in this thread reminds me of how nice grilled snake is.

    When in Guangzhou, PR China, check out the Snake Restaurants. One can even select hisorher own snake from the pit in the same way as selecting a fish at a fish restaurant.

    My first time I thought that I was eating eel as I had been told that it was a fish dish ( the shape meant it would be eel -if it had of been fish-)After my third helping I was informed that I was eating snake. Unfortunately snakes are a protected species here in Australia so I can’t try the local supply even if we do sometimes have a snake in our back yard.

    I’m sure that Grok ate many a snake.\

    I understand that the Chinese remove the bile duct and the poison sac before serving but I have read that the bile duct is too valuable to waste on customers.

  39. Mark

    Most “fish oils” have the DHA and EPA as less than half their oil content. What is the rest of the content? i have asked a number of manufacturers, but all I receive in reply is “spin” about their oils meeting all the required standards.


    1. A lot of fish oils use borage oil and/or vitamin E to fill out the whole of the capsule. The fish oil I take is 70% Omega-3, which I think is pretty good. I use Nordic Natural Ultimate Omega soft gels.

  40. Very definitive indeed! I would love to see a follow-up article Mark, or maybe just a couple of follow-up points.

    For example, how much fish oil would you recommend for someone who has just started a primal diet and is therefore extremely unbalanced both hormonally and in terms of excess body fat? Studies I’ve completed with Charles Poliquin through his BioSignature course indicate 1 gram of fish oil per percentage body fat and actually I’ve had great results with this.

    I really liked your point about possible dangers of fish oil when consuming excess alcohol/sugar. I haven’t come across this before – could be a good warning tactic for newbies!

  41. I wondered whether those that take omega-3 supplements actually feel any benefits? I wouldn’t want to spend years buying and consuming omega-3 supplements for it to have no effect. Or at least no effect that i could not measure.

  42. I’m in college and therefore don’t have a lot of money. There’s no way I could consistantly buy the fish oil supplements and keep up with other expenses without my accounts going into the red. Is there a really good fish I could eat regularly that would get the job done to a degree? Anything else I could do?

    1. Supplements really are the most cost effective way of getting your Omega 3.

      I think the NOW brand is fairly inexpensive but they will give you fish burps.

  43. I know I’m pretty late but all of you should probably read this:

    Ray could be completely wrong, but he makes a convincing argument. Also, if you think about it, fish was probably a minimal part of Grok’s diet (or zero if he didn’t live near a major body of water). If Grok did eat fish they were probably low fat, coastal warm water fish and shellfish, not the high fat cold water fish like tuna.

  44. Hey Mark, This is a really informative article on the health benefits of fish oils. I wasn’t aware that overcooking fish will degrade the amount of omega 3’s available. Maybe I should start eating more sashimi – of course there is the concern of too much mercury from all that raw fish. I guess I’ll stick with my liquid fish oils. I use Carlson fish oils in lemon flavor, but it’s nice to see you’re now offering your own brand of fish oils.

  45. I would like to ask mark if he has heard about
    The sacha inchi oil? A fruit from the jungle of
    Peru. A close cousin of the lignan oil. It is reach
    In omega 3.
    Also do you have any research that can prove that
    The consumption of lignan oil may affect the prostate?

    For people that cannot consume fish oil is there any
    Alternative in the vegetable oil world that you
    Can suggest to use?

    Best regards,

    Juan felix

  46. “Worker Bee”

    What hubris processes an individual to refer to an employee as a “Worker Bee”?

  47. Hi everyone! Im new to MDA and am wondering what brand of fish oil i should take. I am living in Australia so the brands that have been mentioned arent available here. I have found one called Swisse Wild Fish Oil…..”and is one of the only fish oils in the world sourced sustainably from wild fish that swim freely in the pristine waters of the Pacific Ocean free range fish. As a result, Swisse Ultiboost High Strength Wild Fish Oil is free from the high levels of environmental toxins often found in farmed fish….”
    They also have a product called Wild Salmon Oil which has lower EPA and DHA than the fish oil..what are your opinions?

  48. Here is a link to a great fish oil calculator:

    Here is a company that has flavored fish oil without the fish burp and 10% off their listed prices. I have no affiliation…I have just been using and have noticed significant lab value changes as well as the fact that I am just not as banged up any more after my workouts. They have regular sizes as well as travel sizes. Check it out and form your own opinion.

  49. I’m taking Fish oil capsules that contain:

    Total 1000 mg fish body oils

    but that only contains:

    320 mg Omega 3 fatty acids (160 EPA & 160 DHA)

    So to get 1-3 grams Omega 3’s thats 3 to 9 capsules ?


  50. According to
    (where the author brings up an excellent point – Have you ever wondered why a human would suffer from a fish oil deficiency?)

    Claim: Fish oil helps diabetics and helps prevent diabetes and its complications.

    Truth: Resting blood sugars are consistently higher for fish oil users.(see Endnotes:8,9,10) Insulin amounts had to be consistently increased in diabetics who were using fish oil. Glucose tolerance decreased significantly, and the insulin response was significantly blunted (a bad outcome).

    Claim: Fish oil helps your heart and prevents heart disease.

    Truth: Prostacyclin (PGI2(11—the body’s “natural blood thinner”—is the body’ s most potent natural anti-platelet aggregatory agent. It is also a natural anti-adhesive (anti thrombosis) agent. But prostacyclin levels are reduced by an average of 42% in humans with existing atherosclerosis using fish oil.That means fish oil potentially makes existing heart disease worse, not better. Minimizing platelets from “sticking together” or sticking to an arterial wall should be the #1 concern of a patient with existing cardiovascular disease.

    1. hmm… I just started cod liver oil and my sugars have been significantly higher, requiring more injected insulin. I hadn’t made the connection. Thanks for the info.

  51. From what i’ve read, krill oil has higher antioxidant content and since it usually comes in the form of capliques, it doesn’t get rancid easily.

  52. HI;
    I realize that this article and its latest related posts are a year old! However, a fellow health enthusiast I just met, let me know about your website.
    I had heard about Omega-3 and PharmaGrade Fish oil and Silent Inflammation about 7 years ago, from Dr. Barry Sears. He is he author of several books, and apparently appears to be the pioneer in this area, with his ground-breaking work on eating very similar to what you have in PB. His earliest book is about 15 years or possibly earlier, I do not recall, as I only stumbled upon it 7 years ago. I changed my life at that point, and was satisfied that eating helped make me much healthier and through eating lifestyle change lost about 45+ of 60 lbs I needed to lose. Then a few months ago,I finally decided to exercise, and started doing research as to what and how and best. In that search came across the concept of Body weight and started introducing it into my routine. About an hour 2-3 times a week, usually 2 – and mixed stretch warm-up, heavy lift, and peak interval of no more than 10 minutes with all-out included. Similar to what i am learning, here, and now modifying.
    BUT, back t main point, it seems your work is built on a lot if not most of what Dr. Barry Sears pioneered? And is just now recently finding its way more and more into fringes of main stream.

  53. Hi Mark,

    You recommend we bite into a capsule, if it is good then what taste should be expect and if it is bad what taste should be expect?
    Thanks for the great articles!!

  54. I like the fermented cod liver oil for the natural vitamin D.

    I am in Canada where it is hard to find, but I found a supplier here

  55. Hi,

    I’m a bit of a newcomer to this way of life (5 weeks and counting)but I’m already feeling the benefits!

    I eat smoked mackarel every day for my lunch ( 2 fillets)( but it’s bought from a supermarket). I also still have a few beers / wines on the weekend. Am I getting enough Omega 3 or should I add fish oil supplement?

    Great Website by the way…


  56. Hi there, I have tried the Stronger Faster Healthier liquid fish oil and it seems to be good. What is your stance Mark on flavored oils? I am an avid Crossfitter and take 6-9 pills a day before I found the liquid.

    What brand do you suggest or does anyone suggest trying that come in liquid form that have been beneficial to you? I honestly have taken for 4 months strait and dont “notice” an actual physical difference with myself. Or in my training.

    Thanks :)(multi-tasking here)

  57. General question about fish oil supplements … why are the pills so low in fat grams (generally)? Do the producers of fish oil remove some of the natural fat from the oils? Which leads me to my next question – are fish oil pills as effective as liquid cod liver oil? Don’t we ultimately want the unadulterated fish fat grams? Is it detrimental to give the body the Omega 3’s from fish oil without the fat itself?

  58. What about smoked salmon? Where I live, I can net about a hundred salmon a year. Does smoking affect the oil’s properties? We also hot pack can the fish after smoking, which brings it to 330 degrees or so.

  59. I am a bit sad that all this Daily talked about was fish oil in pills. What about fish oil in fish? The oiliest fish tend to be among the most delicious, if you ask me. Great sources of fish oil? How about salmon or bluefish, cooked with the skin on… YUM! Or fatty tuna sushi – chutoro and otoro. Delicious! Or herring and sardines! And if you automatically think of crackers with sardines, try them in a lettuce leaf or on celery with a dab of yogurt or ricotta. Great stuff
    Of course, NOBODY thinks of getting fish oil this way anymore, or they would not leave the scales on fileted fish. (It’s so much easier to scale a fish while it is whole…) This is a pet peeve of mine. I end up with a huge mess in my sink, trying to scale a piece of fish under running water, so the scales don’t fly… But I LOVE the skin on my salmon!

  60. As Stephan explains here – the “here” link links to a post that no longer exists

  61. In all of this, there is one big question that has been left unanswered: if you are going to use an omega-3 supplement, is it better to use a natural form, like wild salmon oil, or carlson’s liquid (both natural triglyceride forms, unprocessed), or should you go for the super concentrated, molecularly distilled or CO2 extracted, highly processed fish oil capsule?

    The natural products are of course lower in omega-3s per serving because they are not artificially concentrated, so…..? Which is it?

    I tend to lean toward wild salmon oil (Solgar’s or Vital Choice’s are good picks), as they have zero chemical residues from heat processing, unlike all concentrated forms of fish oil. There are some who even say that the super concentrated oils are not really even fish oil when you get through with them. They basically are stripped of anything but their EPA and DHA contents, so they are not fish oil.

    Thoughts? This could be an article in itself!

  62. Great write up! We’re planning a blog post on how under-rated fish oil is amongst bodybuilders as a supplement. In fact, if we were stranded on a deserted island and had to choose only 3 supplements fish oil would be #3 after protein and a beastly multivitamin.

  63. Great information. Don’t forget that Omega 3 from microalgae (the original source of Omega 3) is also a great alternative to fish oil.

  64. Thank you very much for the suggestions about fish oil supplements, and its benefits. Yes, I am a person with insufficient omega fatty acids, so I am following a diet including supplements to improve fatty acids. This article has also explained about what is the need to take fish oil and its advantages.