Krill oil does lower triglycerides, though the size of the effect depends heavily on the dose. In clinical trials, high-dose krill oil reduced triglycerides by about 27%, while lower doses produced a more modest 10% reduction compared to placebo. That puts krill oil in a similar ballpark to fish oil on a gram-for-gram basis, but well below the 20% to 40% reductions seen with prescription-strength omega-3 concentrates.
What the Clinical Trials Show
The most relevant trial enrolled 300 adults with borderline-high or high triglycerides (150 to 499 mg/dL) and assigned them to one of four krill oil doses (0.5, 1, 2, or 4 grams per day) or a placebo for 12 weeks. Across all krill oil groups, fasting triglycerides dropped by an average of 10.2% compared to placebo. The effect was dose-dependent, meaning higher intakes produced larger reductions.
An earlier 12-week trial in patients with more significantly elevated cholesterol and triglycerides found that a high-dose krill oil group achieved a 27% triglyceride reduction. Lower doses in that same trial didn’t reach statistical significance, reinforcing the pattern: you need enough krill oil for a meaningful change.
Most trials measure results at 6 and 12 weeks, so if you’re tracking your own blood work, plan on at least three months of consistent use before expecting to see a clear shift in your numbers.
How Krill Oil Compares to Fish Oil
A network meta-analysis that pooled data from multiple studies found that one gram of omega-3 fatty acids from krill oil lowered triglycerides by about 9.8 mg/dL, while the same amount from fish oil lowered them by about 9.0 mg/dL. The difference was not statistically meaningful. In practical terms, the triglyceride-lowering effects of krill oil and fish oil are equivalent when you match the actual omega-3 content.
Where krill oil does differ is in how the omega-3s are packaged. In fish oil, the EPA and DHA are bound to a fat molecule called a triglyceride. In krill oil, they’re bound to phospholipids, a type of fat that integrates more easily into cell membranes. Animal research shows that this phospholipid form leads to greater incorporation of omega-3s into red blood cell membranes (a marker called the omega-3 index) and more effectively activates fat-burning pathways in the small intestine. This enhanced absorption is why krill oil can sometimes match fish oil’s results at a slightly lower total dose, even though its omega-3 concentration per capsule is lower.
Dose Matters More Than the Label
Most over-the-counter krill oil capsules contain 500 mg to 1,000 mg of krill oil, but only a fraction of that is actual EPA and DHA. A typical 1,000 mg krill oil softgel delivers roughly 120 to 200 mg of combined EPA and DHA. Compare that to a standard fish oil capsule, which often provides 300 mg or more.
The AHA notes that 2 to 4 grams of EPA and DHA per day can lower triglycerides by 20% to 40%. Reaching that range with krill oil alone would mean taking a large number of capsules daily, which is neither practical nor cost-effective for most people. The 10% to 27% reductions seen in krill oil studies used total krill oil doses of 2 to 4 grams per day, which translates to a much smaller amount of actual omega-3s than what prescription formulations provide.
If your triglycerides are mildly elevated (say, 150 to 200 mg/dL), a moderate krill oil dose combined with dietary changes could be enough to bring them into a healthy range. If your levels are above 300 or 400 mg/dL, krill oil alone is unlikely to close that gap.
Why Phospholipids Change Absorption
The omega-3s in krill oil are more bioavailable because phospholipids are the same type of fat that makes up your cell membranes. Your gut absorbs them through a slightly different route than regular dietary fats, which allows more of the EPA and DHA to enter your bloodstream intact. Research in animal models found that krill oil’s phospholipid-bound omega-3s activated genes involved in burning fatty acids in the intestinal lining more effectively than the same dose delivered in standard triglyceride form. This increased fat oxidation in the gut itself may partly explain how krill oil influences overall lipid levels.
Effects on Other Cholesterol Numbers
Triglycerides are only one piece of your lipid panel. In the clinical trials, krill oil’s effects on LDL (“bad” cholesterol) were generally neutral, meaning it didn’t push LDL up or down in a significant way. This is actually a useful feature: some triglyceride-lowering interventions can inadvertently raise LDL, so a supplement that lowers triglycerides without worsening other markers has a cleaner profile. The data on HDL (“good” cholesterol) is less consistent, with some trials showing small increases and others showing no change.
Safety and Blood-Thinning Concerns
Because omega-3s have mild anti-platelet effects, krill oil is often flagged as a concern for people on blood thinners like warfarin. The clinical evidence, however, is reassuring. A retrospective study of patients taking warfarin for atrial fibrillation or deep vein thrombosis found that fish and krill oil supplementation did not significantly alter warfarin control, time in therapeutic range, or the incidence of bleeding events. Before this study, the entire body of evidence for this supposed interaction consisted of just three case reports with conflicting results.
The AHA does recommend that anyone taking more than 3 grams of omega-3 fatty acids per day from supplements do so under medical supervision, since very high doses can affect clotting time. At the doses found in typical krill oil regimens (1 to 4 grams of krill oil, not pure omega-3), this threshold is rarely approached.
What to Realistically Expect
Krill oil is a legitimate tool for modestly lowering triglycerides, particularly if your levels are in the borderline-high range. At doses of 2 to 4 grams per day, you can expect a roughly 10% to 27% reduction over 12 weeks. It won’t replace prescription-strength omega-3 therapy for people with very high triglycerides, but for mild to moderate elevations, it offers a convenient option with good absorption and a low side-effect profile. The triglyceride-lowering power per gram of omega-3 is essentially the same as fish oil, so the choice between the two comes down to tolerance, cost, and personal preference rather than a clear efficacy advantage.