Krill Oil vs. Fish Oil: Battle of the Omega-3 Fats

krill oil vs. fish oil
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Omega-3 fatty acids like fish oil and krill oil are getting a lot of attention in the media as superfoods and healthy fats, and deservedly so.

EPA and DHA are “essential” fatty acids, meaning that we can’t make them in our body and need to get them from our food, and they are necessary for proper functioning, particularly in your brain. DHA plays a very important role in your nervous system functioning, provides anti-inflammatory benefits, and is also associated with improved mood, insulin sensitivity, muscle growth, and better sleep.

And your body can actually turn EPA into DHA if your desaturase enzymes are working…

So which is better for you, krill oil or fish oil?  Watch it here:

Taking adequate amounts, around 1 gram a day, of krill oil or a high quality fish oil, can do wonders for keeping your brain performing at its highest levels. You can also eat seafood, something I heartily encourage on the Bulletproof Diet Roadmap (get it for free here).

Why Krill Over Other Omega 3 Oils?

Krill oil is a superior source of EPA and DHA because the polyunsaturated fats are packaged as phospholipids, which can be used immediately by your body. The EPA and DHA in fish oil, on the other hand, are typically packaged as triglycerides and have to undergo additional processing in order to make them bioavailable. Krill oil is also more stable because it includes astaxanthin, a powerful antioxidant, that protects the fragile fats from oxidizing. I take extra astaxanthin every day!

Animal-based omega-3’s from krill and fish oils are both better sources than vegetable-based omega-3’s, such as the Alpha-linolenic Acid (ALA) in flax oil. Only about 1-4% of ALA is converted into DHA, so getting those higher potency sources from krill and fish is more efficient. Vegetable-based sources also contain oxidized inflammatory omega-6 fatty acids, which is another reason that they aren’t Bulletproof.

Taking too much EPA and DHA can be detrimental since they do cause blood thinning, they can suppress healthy levels of arachidonic acid (AA),  and delicate fish oils can be inflammatory since they break down so easily in light or heat or air.

The reason why the phospholipid form found in krill oil is easier for the body to use is that the majority of every cell membrane in the body is made of phospholipids. Cell biologists talk about all the other components in cell membranes floating in a sea of phospholipids. Omega-3s phospholipids make cell membranes more fluid and flexible. Meanwhile, triglycerides are how lipids are stored for later use and transport in the body, such as in adipocytes (fat cells), so it takes more steps to get fish oil omega-3s into cell membranes where they’re needed the most.

Watch out – low quality supplement manufacturers make “krill oil” that has a small amount of krill and a lot of much cheaper fish oil. Be sure you’re getting 100% krill oil! Quality matters.

When taken incorrectly, the less desirable effect of fish oils may be due in part to them being oxidized so quickly and overwhelming the liver. Because of the astaxanthin, krill oil doesn’t likely carry the same risk. To learn more check out “The Great Fish Oil Experiment,” by Ray Peat.

Your Dose of Omega-3 Knowledge For The Day

Omega-3s are one of the most popular health-related search terms ever – for good reason!  For an awesome explanation of the science behind healthy and high quality fats check out this science post on omega-3 versus omega-6 fats.

As you’ll find on the Bulletproof Diet, amazing sources of omega 3s include wild salmon, grass-fed beef, algae oils, sardines, Brussels sprouts, cauliflower, walnuts and flaxseeds. You can also optimize omega 3s through superior supplements like Krill oil.  There are three common types of omega 3 fatty acids for you to know about: EPA, DHA, and ALA.

1 and 2)  EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – both are long chain omega 3 fatty acids, and both come from animal sources. DHA is the really good one: it keeps your nervous system functioning and provides anti-inflammatory benefits. Higher consumption correlates with improved mood, greater insulin sensitivity, increased muscle growth, and better sleep.

3) ALA (alpha-linolenic acid) – this is a short chain omega 3 fatty acid. ALA comes mostly from plant sources, and most animals can’t really use it, so they convert it to the super-powerful DHA we just talked about.
Herbivores and opportunistic omnivores like mice and rats are great at converting ALA to DHA. Humans, on the other hand, can only convert about 8% of ALA to DHA. That’s one reason why chia seeds and flaxseed oil don’t rank particularly high on the Bulletproof Diet Roadmap. The people selling chia seeds are quick to tell you that their product is high in omega 3s; what they fail to mention is that the omega 3 isn’t the right kind. You still convert some of it to DHA, but getting your DHA directly from animal sources is much more efficient.

TLDR?  Take small quantities of the highest-quality source possible (whole wild salmon or krill oil or whole wild salmon oil) and you’ll be a happy camper.

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By Dave Asprey

  • nicka

    Why not use Eskimo-3 fish oil – 1 5ml daily amount has loads more epa/dha than krill oil

    • Although you may find higher levels of EPA and DHA on the labels of fish oil, the bioavailability is much greater in Krill Oil, so you’ll see the same benefits with smaller amounts.

  • msmonkeymind

    If you want to raise your omega-3 index, which is a major reason to take omega-3, the most efficient and cost effective way of doing this is rTG omega-3 fish oil. The average dose of krill oil doesn’t increase the omega-3 index as much as plain old TG salmon oil! See this paper:

    • Maxy

      Lovely, I’ll keep taking my Nordic Naturals Fish Oil.

  • Maxy

    So how many of these Jarrow Krill Oil capsules do you take per day?

  • Krill oil for astaxanthin is stupid because you’re only getting a tiny % of, say, a proper pill of pure astaxanthin

    astaxanthin is in krill oil only in trace amounts.

  • Matt

    I’ve known a thing or two about krill/fish oil for some time, but recently spent some time going back and researching ordering either a bulk order of Viva Lab’s krill oil or Vital Choice’s wild sockeye salmon oil… Both came out on top for whole fish oil/krill oil supplementation for me, and costs were relatively similar for me as well. I ended up settling on VL’s krill oil because of the higher bioavailability of the phospholipid composition and its 1.7mg/serving of astaxanthin (the salmon oil has astanxanthin as well, but in much lower concentration)… And because,
    I prefer to get my astaxanthin along with my O-3’s more naturally in phospholipid form than separately and having to purchase a separate supplement (I already take enough).
    In conclusion: Krill oil is much lower in EPA/DHA, but is more bioavailable and efficiently absorbed than fish oils (triglycerides) due to its phospholipid structure. Thus, a smaller amount of KO yields a higher equivalent dose of FO. Furthermore, if you purchase the right (good quality) source of KO, it actually can contain a significant source of astaxanthin (I get roughly 10-12mg per week through KO supplementation alone; that’s just shy of “therapeutic” doses).

    Due to my recent research, I am weary of the efficacy of many refined fish oil supplements (probably most, save for ones such as the aforementioned salmon oil from VitalChoice and the like, which are left naturally intact). There’s research which suggests these refined tryglyrceride forms may not be very bioavailable on their own(a 500mg EPA/DHA dose does not equal 500mg EPA/DHA once assimilated into your cells; perhaps only a couple hundred mg), and that using lower EPA/DHA concentrated, but more naturally occurring formulations is more effective. Ergo, by opting for Krill oil over FO supplements, I ensure that I am getting a more in-tact, natural lipid profile with higher bioavailability, as well as the tertiary astaxanthin which also helps to stabilize and preserve the oil while in storage/transit/usage.

    That’s my .02…. or maybe $2, but hopefully this helps make some more sense as to why one might choose to supplement with krill oil versus normal fish/cod liver oils.


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  • I’m wondering what your thoughts are about krill decomposition. It’s my understanding that krill will start to decompose much faster than fish when extracting oils. My concern is, then, right up your alley… Is it rotting? Am I more likely to consume mycotoxins with krill oil than fish oil?

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  • Jason Wortham

    Ok, So the article had me intrigued. So I went to Amazon to try to find a good source for Krill oil. My favorite DHA brand is Now-Foods, where a 1000mA gelcap has 500mg DHA, 250mG EPA, and 250mA other stuff. It seemed like the most potent DHA on the market, but it’s fish oil, not Krill oil.

    Also, my opinion is that fish-oil or Krill oil really needs to be maximized for DHA content, and I generally disregard EPA. I’ve personally felt super-sharp a couple of times after consuming DHA, and I was quite impressed.

    A typical Krill oil gel-cap brand contains a pathetic 40mg in a 1000mg serving (2 gelcaps). I’m getting 20x less DHA, so something sounds wrong. Doctor’s best contains 256mg per 400mg gelcap, so that’s better, but still 2x off of the fish oil that I can buy.

    So does the Krill oil advantage outweigh the lower DHA content?

    • Jason Wortham

      Also, the Dr’s Best brand Krill oil (with the higher DHA content) is actually Krill+Fish Oil. I think they just can’t get the same high DHA content from Krill oil, or I can’t find where to buy it. Anyone know of a 500mg DHA gelcap Krill oil source? Or at least greater than 20mg DHA per pill?

      • Peter Diller

        Kirkland has a 500mg of Krill Oil ( available @ Costco ) DHA 30 mg, EPA 60 mg, Omega 3 fatty acids 120 mg, Astaxanthin 150 mcg

        • Jason Wortham

          It seems I’d still need to consume 16 of the Kirkland caps to get the 500mg pure DHA that I get in a single cap of fish oil. Not gonna consume 16 per day.

  • AK

    I’ve been taking a daily capsule of Seven Seas Extra High Strength for many years.

    Are there better Omega-3 supplements available out there? If yes, please advise which and explain why. Thanks.

    (33, male, active, good health).

  • BC

    Great article, as usual. Question. I currently take NOW’s Neptune Krill 1000. On the supp facts label it reads, per 1 pill serving
    Neptune Krill 1g
    Omega-3 Fatty acids 230mg
    EPA 120mg
    DHA 70mg
    Phospholipids 390mg
    Esterfied Astaxanthin 750mcg

    Is taking one of these pills adequate for what Dave is recommending? or should I be simply looking at the EPA & DHA amounts, should those total 1 gram? If that’s the case have I been taking pretty much a placebo dose?

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  • Jack Napierre

    I find that when I take a big dose of krill any time of the day eg) 3 grams. I go to sleep just fine but wake up 4-5 hours earlier than I normally would. Is the krill making me ‘sleep faster?’ or is it causing me to skip important sleep stages? Hard to tell.

    I use sleep cycle, and it showed poor sleep quality. But I’ve had it misread my sleep before so not totally reliable imo.