Krill oil can modestly improve your cholesterol profile, particularly by lowering triglycerides without raising LDL (“bad”) cholesterol. It’s not a replacement for medication if you have significantly elevated cholesterol, but the evidence supports it as a useful supplement for people with borderline or mildly high lipid levels looking for additional support.
What Krill Oil Does to Your Lipid Numbers
The clearest benefit of krill oil shows up in triglycerides, a type of fat in your blood that contributes to cardiovascular risk when elevated. In a randomized, placebo-controlled trial of 300 adults with borderline high or high triglyceride levels, krill oil supplementation lowered triglycerides without increasing LDL cholesterol. That second detail matters: some lipid-lowering strategies can improve one number while worsening another, so a supplement that brings triglycerides down while leaving LDL stable is doing useful work on two fronts.
The effects on HDL (“good”) cholesterol and total cholesterol are less dramatic. Some smaller studies have reported slight increases in HDL with krill oil use, but the improvements tend to be modest. If your primary concern is very high LDL cholesterol, krill oil alone is unlikely to move the needle enough to make a meaningful difference. It’s better understood as a triglyceride-focused supplement with a generally favorable effect on your overall lipid balance.
Why Krill Oil Absorbs Better Than Fish Oil
Krill oil and fish oil both deliver EPA and DHA, the two omega-3 fatty acids linked to heart health. The difference is in how those fats are packaged. In fish oil, EPA and DHA are bound to triglycerides or ethyl esters. In krill oil, a significant portion (roughly 28 to 58 percent) is bound to phospholipids, specifically a type called phosphatidylcholine. Phospholipids mix more easily with the watery environment of your gut, which makes them easier for your body to absorb.
The numbers back this up. In a direct comparison using equal amounts of oil (1,680 mg), krill oil was absorbed about 33 percent better than standard fish oil triglycerides and 68 percent better than fish oil ethyl esters. This means you can take a smaller dose of krill oil and still get a comparable amount of omega-3s into your bloodstream. It’s one reason krill oil capsules tend to be smaller than fish oil capsules, which some people find easier to tolerate.
The Astaxanthin Bonus
Krill oil contains astaxanthin, a natural pigment responsible for the reddish color of krill, shrimp, and salmon. Astaxanthin acts as an antioxidant, meaning it helps neutralize free radicals that can damage cells and contribute to inflammation. This gives krill oil a practical advantage over fish oil in two ways: it helps protect the oil itself from going rancid (a common complaint with fish oil supplements), and it may offer additional anti-inflammatory benefits on top of the omega-3s. The Cleveland Clinic notes that astaxanthin has shown both anti-inflammatory and antioxidant properties, with potential protective effects on the brain and nervous system.
How Much to Take
Clinical research has tested krill oil at doses ranging from 500 mg to 4 grams per day. Most supplement brands sell capsules in the 500 mg to 1,000 mg range, and the commonly recommended dose for general heart health falls between 1 and 2 grams daily. Higher doses (closer to 4 grams) were used in clinical trials targeting elevated triglycerides, so if your triglycerides are your main concern, the lower end of the dosing range may not be enough to produce noticeable results.
Because krill oil is better absorbed than fish oil, you don’t necessarily need to match fish oil doses gram for gram. Taking 1 to 2 grams of krill oil delivers a comparable omega-3 payload to a higher dose of standard fish oil. Most people take it with food, which further improves fat absorption.
Safety and Blood Thinners
Krill oil is generally well tolerated. The most common complaints are mild digestive issues like fishy burps, nausea, or loose stools, though these tend to be less frequent than with fish oil, partly because of the smaller capsule size and better absorption.
One persistent concern is whether krill oil interacts with blood-thinning medications like warfarin. Omega-3 supplements have been flagged as a potential interaction risk because they can have mild blood-thinning effects of their own. However, a retrospective study of patients taking warfarin for atrial fibrillation and deep vein thrombosis found that fish and krill oil supplementation did not significantly alter warfarin control or increase the incidence of major or minor bleeding events. That said, if you’re on anticoagulants, it’s worth discussing any new supplement with your prescriber so they can monitor your levels if needed.
If you have a shellfish allergy, use caution. Krill are crustaceans, and while the allergenic proteins in shellfish are concentrated in the flesh rather than the oil, the risk of a reaction isn’t zero. People with severe shellfish allergies should avoid krill oil or discuss it with an allergist first.
Krill Oil vs. Prescription Options
It’s worth being realistic about what krill oil can and can’t do. For people with mildly elevated triglycerides or those looking to maintain already-decent cholesterol numbers, krill oil is a reasonable option that improves absorption, avoids LDL increases, and comes with added antioxidant benefits. For people with very high cholesterol or established cardiovascular disease, krill oil is not a substitute for prescription medications, which can lower LDL by 30 to 50 percent or more. Krill oil operates on a different scale, offering modest, supportive improvements rather than dramatic reductions. It works best as one piece of a broader approach that includes diet, exercise, and medical treatment when warranted.