Cod liver oil and krill oil sound like two versions of the same thing. They aren’t. Cod liver oil is really a vitamin product — its headline act is preformed vitamin A and vitamin D, with some omega-3 riding along. Krill oil is a narrow omega-3 product: EPA and DHA, plus the red antioxidant astaxanthin, and no fat-soluble vitamin load at all. So the honest answer isn’t “which is better.” It’s “which gap are you actually filling?”
We sell Captains Krill Oil, so read the rest with that in mind. But we’ll say the unflattering part first: if the thing you’re short on is winter vitamin D, cod liver oil does a job our krill oil simply can’t. Here’s the whole picture, honestly.
They come from different parts of the fish — and it shows
Cod liver oil is pressed from the liver of the cod. The liver is where a fish concentrates fat-soluble vitamins, so the oil comes out loaded with vitamin A (as retinol) and vitamin D, plus a modest amount of omega-3. Krill oil is pressed from Antarctic krill — a whole tiny animal, not an organ — so it carries omega-3 and astaxanthin but essentially none of the vitamin A or D that makes cod liver oil what it is.
That single difference drives everything else. Buy cod liver oil and you’re mostly buying vitamins A and D. Buy krill oil and you’re buying omega-3 in a different chemical vehicle. Confusing the two is how people end up double-dosing one nutrient and missing another entirely.
The vitamin A ceiling nobody mentions
Here’s the part the glossy cod-liver-oil ads skip. Preformed vitamin A (retinol) is fat-soluble — your body stores it rather than flushing the excess — and it has a real upper limit. The tolerable upper intake level for adults is 3,000 micrograms RAE per day, per the NIH Office of Dietary Supplements. A single teaspoon of standard cod liver oil can carry roughly 400 to over 1,300 micrograms RAE of vitamin A, and some “high-vitamin” versions carry far more.
On its own, a teaspoon is usually fine. The problem is stacking. Add cod liver oil on top of a multivitamin that already contains retinol, plus the odd serving of actual liver, and you can quietly drift toward — or past — that ceiling without noticing, because nothing about it feels like an overdose. Chronic excess retinol is genuinely worth avoiding, which is why cod liver oil is one of the few supplements where “more” can work against you.
Vitamin D has a ceiling too — 100 micrograms (4,000 IU) per day for adults, per the NIH ODS — but a teaspoon of cod liver oil (typically 400–800 IU) leaves plenty of room. It’s the vitamin A you watch. Krill oil sidesteps this whole question: no retinol, no fat-soluble vitamin stack to blow through.
Omega-3: more per teaspoon in krill, but you take them differently
Gram for gram of oil, krill tends to carry more omega-3 than cod liver oil. But nobody takes them the same way: cod liver oil is a teaspoon or tablespoon; krill oil is a small capsule. So the real comparison isn’t spoon-to-spoon — it’s how much EPA and DHA lands on your label, and what form it’s in.
Krill’s omega-3 comes mostly bound to phospholipids; cod liver oil’s comes as triglycerides. Krill sellers (us included) like to point at the phospholipid form and claim better absorption. The honest version: the molecule that reaches your blood — EPA and DHA — is the same either way, and the “krill absorbs better” claim rests on a handful of small studies, not a mountain of them. We wrote a whole piece on that: same molecule, different vehicle. Don’t pay a big premium on the absorption argument alone.
How ours is made — and why we’ll tell you
Captains Krill Oil is pressed mechanically, on the boat, without solvents — closer to squeezing an orange than running a chemistry set. It’s a natural catch, so the omega-3 numbers vary a little lot to lot; we don’t blend or standardize the oil in a factory to hit a chosen figure on a box. We test lots at random and they come back strong, and documentation is available on request. Twenty years of doing it the same way is the whole reason we can answer questions like this one plainly.
Any brand — cod liver oil or krill — should be able to tell you how their oil was made and roughly what’s in it. If they can’t, keep your money.
You might not need either
If you eat oily fish — salmon, sardines, mackerel — about twice a week, you’re likely getting enough EPA and DHA from your plate, and you don’t need a krill capsule or a cod liver spoon for omega-3. See dietary sources of omega-3 before you buy anything.
If your actual gap is vitamin D in a dark winter, cod liver oil is the older, cheaper answer — or just a plain D3 supplement, which lets you dose vitamin D without dragging vitamin A along for the ride. Our krill oil can’t do that job, and we’re not going to pretend it can.
Where krill earns its place: you’re already covered on vitamins A and D, but there’s not much fish on your plate, and you want omega-3 without the fishy repeat or the retinol load. That’s the narrow lane Captains is built for. Dose to your goal and your blood work, not to a number on a box.
Frequently asked questions
Can I take krill oil and cod liver oil together?
You can, but there’s rarely a reason to, and you should watch your total vitamin A if you do. Cod liver oil brings retinol; krill oil brings extra omega-3 you may not need on top of it. If you already take cod liver oil for vitamin D, adding krill is just more omega-3 — useful only if your diet is genuinely short on it.
Does cod liver oil have more omega-3 than krill oil?
Per equal amount of oil, krill usually carries more omega-3 than cod liver oil. But they’re dosed differently — spoonfuls of cod liver oil versus small krill capsules — so compare the EPA and DHA totals on each label rather than assuming one wins. Cod liver oil’s real draw is its vitamins A and D, not its omega-3 count.
Is cod liver oil safe in pregnancy?
This is the big exception. Cod liver oil is high in preformed vitamin A, and too much retinol in pregnancy is linked to birth defects, so most guidance is to avoid cod liver oil while pregnant and get omega-3 from low-retinol sources instead. Talk to your doctor, and if you want omega-3 without the vitamin A load, that’s exactly the difference krill oil offers. This isn’t medical advice — your provider knows your situation.
Which is better for your heart?
For the omega-3 job that heart guidance actually tracks — lowering triglycerides — what matters is your total EPA and DHA, not whether it came from krill or cod. Both can contribute. Neither is a heart drug, and no supplement replaces diet, exercise, or the medication your doctor prescribes.
Why is krill oil more expensive?
Krill oil typically costs several times more per omega-3 dose than fish or cod liver oil, partly because of harvesting and processing, partly because of the astaxanthin and phospholipid marketing. If price is your deciding factor and you just want omega-3, cheaper options exist. If you want a clean, narrow omega-3 with no vitamin A load and you value how it’s made, that’s the case for paying more — but we’d rather you decide that than have us decide it for you.
Honest answer, not a pitch. — captainskrilloil.com