How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Krill oil
Krill oil slightly lowers triglycerides (by 10% in a trial of 300 adults) and LDL cholesterol. For osteoarthritic knees, results are contradictory: the largest trial found no effect on pain.
Benefits
- Triglycerides: in 300 adults with high triglycerides, 12 weeks of krill oil lowered them by 10.2% compared to the placebo, without increasing LDL cholesterol.
- Cholesterol: in a meta-analysis of 14 trials and 1,458 participants, total cholesterol, LDL, and triglycerides decreased; another, involving 7 trials and 662 participants, also observed an increase in HDL.
- Knee osteoarthritis: in 235 adults with mild to moderate osteoarthritis, 4 g per day for 6 months slightly reduced pain and stiffness and improved knee function.
- Knee function: across 5 trials and 700 patients, a small effect on knee function (0.24); another meta-analysis of 5 trials (730 participants) found less pain, stiffness, and discomfort on the WOMAC questionnaire.
- Muscle after age 65: in 94 inactive older individuals, 4 g per day for 6 months increased thigh strength, grip strength, and thigh muscle thickness compared to the placebo.
- Recovery: in 30 young resistance-trained men, 3 g per day limited muscle damage (lower creatine kinase) and helped strength return after a demanding training session.
- Skin: in 101 adults, 1 or 2 g per day for 12 weeks reduced skin water loss and improved hydration and elasticity, all the more so as the dose was higher.
- Blood omega-3: in 35 strength athletes, 2.5 g per day for 12 weeks increased the omega-3 index from 4.82% to 6.77%; at an equal dose of omega-3, a trial on 72 adults measured 1.5 times more EPA and DHA in the blood than with fish oil.
Precautions
Tolerance: in the 24-week trial on 262 people, 51% experienced at least one adverse effect with krill oil, compared to 54% with the placebo; a meta-analysis of 5 trials concluded that safety is similar to standard care. Limitations: knee pain: in the largest trial (262 people with osteoarthritis and effusion), pain decreased just as much with krill as with the placebo; a meta-analysis of 700 patients found no effect on pain or stiffness. Heart: a meta-analysis of 14 trials found no effect on blood pressure, blood glucose, body composition, or markers of inflammation; in 113 healthy volunteers, 7 weeks did not change blood fats. Weight: in 26 overweight women, 3 g per day for 8 weeks changed neither waist circumference nor abdominal thickness. Sports: in 37 young adults, 2 g per day for 6 weeks did not improve a cycling time trial. Adolescents: in 267 adolescents, one year of krill oil did not improve cognitive tests; in a one-year Dutch trial, there was also no effect on depressive symptoms or self-esteem.
Recommended dosage
Trials: 0.5 to 4 g of krill oil per day, from 4 weeks to 6 months; 2 g for the knee and skin, 4 g for muscle after age 65.
How to take it
- Dose: regarding triglycerides, the trial of 300 adults combined four doses (0.5, 1, 2, and 4 g per day); it did not specify which one is sufficient.
- Knee: 2 g per day for 24 weeks had no effect on pain in 262 people; 4 g per day for 6 months provided slight relief for 235 adults.
- Muscle: the positive trial administered 4 g per day for 6 months to individuals over 65 who exercised for less than one hour per week.
- Duration: over 12 weeks, the omega-3 index increased by 1.15 points with krill, just as much as with fish oil or Calanus oil.
- Krill or fish: at an equal dose of EPA and DHA, 66 adults reached similar blood levels in 4 weeks, and regarding blood lipids, a network meta-analysis of 64 trials found no difference between the two.
Did you know?
At an equal dose of omega-3, krill oil increased blood EPA and DHA 1.5 times more than fish oil in 72 adults, and in women, EPA increased 1.5 times more than in men.
What the studies say
This meta-analysis of randomized clinical trials evaluated the efficacy of krill oil for knee osteoarthritis in 730 participants. The study showed no significant improvement in pain according to the visual analogue scale, but significant benefits were observed for pain, stiffness, and physical function according to the WOMAC index. The safety profile of krill oil was similar to that of usual care.
Meng J, Wang X, Li Y, Xiang Y, Wu Y, Xiong Y, Liu P, Gao S. — Medicine (2025) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more