Modestly, and mostly triglycerides — and only at a dose roughly double what a standard bottle gives you. The pooled trial evidence shows real movement in blood fats; the single best-designed trial at four grams a day found no change in fasting triglycerides at all. Both of those things are true, and most krill oil pages only tell you the first one.
Here is the whole picture, numbers included.
First, a word the label and your blood test both use
“Triglyceride” means two different things in this conversation and the confusion sells a lot of supplements.
On a blood panel, triglycerides are a fat circulating in your bloodstream — the number your doctor watches. On a fish oil bottle, “triglyceride form” describes the chemical vehicle the omega-3 rides in, which is a completely separate subject. Krill oil carries its EPA and DHA on phospholipids instead. That is a real difference in the vehicle, and we wrote about it in phospholipid vs. triglyceride omega-3s. It is not a claim about what happens to the number on your lab report.
This page is about the lab report.
What the pooled trials actually found
The most-cited analysis is Ursoniu and colleagues, published in Nutrition Reviews in 2017. They pooled 7 randomized controlled trials — 14 treatment arms, 662 people, 427 on krill oil and 235 on control. The results:
- LDL cholesterol down about 15.5 mg/dL
- Triglycerides down about 14.0 mg/dL
- HDL cholesterol up about 6.7 mg/dL
- Total cholesterol: moved, but not enough to reach statistical significance
Those are respectable numbers. (Ursoniu et al., Nutrition Reviews 75(5):361.)
Now the sentence buried in the same paper that nobody quotes: the effective dosages were at least 2 grams a day, for at least 12 weeks.
A standard krill oil serving — ours included — is one gram a day. Two softgels. If you take the label dose and expect the meta-analysis result, you are taking half the dose that produced it, and the studies that produced it ran for three months. That is not a knock on krill oil. It is arithmetic, and you deserve to have it done in front of you before you buy anything. We go into the whole dose question in how much krill oil you should take a day.
The trial that found nothing
In 2018, Norwegian researchers ran the experiment properly in the Journal of Nutritional Science: 36 adults with mildly elevated fasting triglycerides, randomized for 8 weeks to krill oil, to eating lean and fatty fish per dietary guidelines, or to a control oil. The krill group took eight capsules a day — 4 grams of oil, four times a typical serving.
Fasting triglycerides did not change between the groups. Not in the krill arm, not in the fish arm. The krill oil did shift the lipid content of the smallest VLDL particles and did slightly better than fish on blood glucose, but the headline number — the one people buy krill oil for — sat still. (Journal of Nutritional Science, 2018.)
We sell krill oil and we are telling you about the null trial, because you will find it eventually and we would rather you heard it here.
The part that should genuinely give you pause
Omega-3s pull triglycerides down. They can also push LDL up.
The NIH Office of Dietary Supplements states it plainly: higher intakes of EPA and DHA reduced triglycerides and raised HDL, and also raised LDL (NIH ODS omega-3 fact sheet). In the lipidology literature the rise runs roughly 5–10% at 4 grams a day of a mixed EPA/DHA product, and the effect tracks with how hard the triglycerides fall — the harder the drop, the more the LDL tends to drift. Purified-EPA prescription products don’t show it; mixed EPA and DHA products do.
Krill oil is a mixed EPA and DHA oil. Nobody has run that specific question at scale in krill, which means the honest answer is: we don’t know how much of that applies to krill, and anyone who tells you it definitely doesn’t is guessing. If you are taking omega-3 for your lipids, get the panel redrawn in three months and look at all four numbers, not the one you were hoping to move.
What krill oil did not move
A 2023 systematic review in Diabetes & Metabolic Syndrome updated the picture and found the lipid benefits again — total cholesterol, LDL, triglycerides. It also found no effect on systolic or diastolic blood pressure, fasting glucose, insulin, HbA1c, HOMA-IR, body weight, BMI, waist circumference, or C-reactive protein (2023 updated meta-analysis).
And one wrinkle worth naming, because it argues against us: the lipid effects clustered in trials that were shorter than 8 weeks and in leaner participants. The 2017 analysis said the effect needed 12 weeks. Those two findings don’t sit comfortably together, and when subgroup patterns disagree like that it usually means the underlying effect is smaller and shakier than the headline suggests.
You might not need us
If your triglycerides are genuinely high — the 200 to 499 mg/dL range or above — a krill oil capsule is not the tool. The American Heart Association’s 2019 science advisory reviewed 17 trials and concluded that 4 grams a day of prescription omega-3 lowers triglycerides by 20 to 30% (Skulas-Ray et al., Circulation 2019;140:e673). That is a doctor’s conversation and a prescription, not a supplement purchase. Getting four grams of omega-3 out of any consumer krill oil would mean swallowing a small handful of capsules daily at a price nobody should pay.
Two more honest exits:
- You eat fatty fish twice a week. The Norwegian trial’s fish arm did about what the krill arm did. Sardines, mackerel and canned salmon are cheaper than us and come with dinner attached.
- You are on a statin and your numbers are fine. A statin is doing the LDL job already. Adding an omega-3 for cholesterol reasons is chasing a small effect on top of a large one — see our answer on taking krill oil with Lipitor. Talk to whoever prescribed it.
Where Captains fits
We do not claim our oil will move your cholesterol. What we can tell you is what is in the bottle and how it got there.
Captains Krill Oil™ is pressed mechanically from fresh-caught Antarctic krill, right on the boat, with no chemicals at any stage. It is not shipped as meal across the world to be reprocessed months later. It is a natural catch, so it varies a little lot to lot — we test lots at random and they come back strong, and documentation is available on request. Twenty years of doing it that way.
None of that changes the trial evidence above. It just means that when you decide what the evidence is worth, you know exactly what you would be taking.
Quick answers
Does krill oil lower LDL cholesterol?
Pooled trials found LDL about 15.5 mg/dL lower on krill oil, but the effective doses were 2 grams a day or more for at least 12 weeks. At the same time, the NIH notes that omega-3 intake overall can raise LDL. Have your panel redrawn rather than assuming a direction.
How long does krill oil take to affect cholesterol?
The 2017 meta-analysis found the clearest effects in trials running 12 weeks or longer. Three months is the honest window before a repeat blood test tells you anything. Anything you read at four weeks is noise.
Is krill oil better than fish oil for triglycerides?
There is no strong evidence that it is. The 2018 Norwegian trial compared krill oil against eating lean and fatty fish at matched omega-3 intake and neither moved fasting triglycerides. Krill’s phospholipid vehicle absorbs well, but absorption is not the same thing as a lipid result.
Can I take krill oil with a statin?
Many people do, and there is no well-established interaction, but this is a question for your prescriber and not for a supplement label. If your LDL is already controlled on a statin, adding krill oil for cholesterol reasons is chasing a small effect on top of a large one.
What dose of krill oil did the cholesterol studies use?
At least 2 grams a day in the trials where effects showed up — roughly double a standard one-gram serving. The 2018 null trial used 4 grams a day and still saw no triglyceride change, which is why we would rather you knew the dose figures than the headline.
This article is information, not medical advice. Blood lipids are a conversation to have with your doctor, with a blood test in hand.
Honest answer, not a pitch. — captainskrilloil.com