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.
Omega-3
The EPA and DHA fatty acids from fatty fish. They slightly lower blood pressure, and triglycerides at high doses, but as a supplement they do not protect the heart and do not build muscle in healthy adults.
Benefits
- Lower blood pressure slightly: −1.5 mmHg systolic on average across 70 trials, and −4.5 mmHg in untreated hypertensives
- Lower triglycerides by 27% at 3.4 g per day of EPA + DHA for 8 weeks, in adults with moderately elevated triglycerides (0.85 g per day changed nothing)
- After 60 years of age, slightly more muscle: +0.33 kg on average across 10 trials; in a six-month trial, +3.6% thigh volume and +2.3 kg grip strength
- Fewer markers of muscle damage after exercise (creatine kinase, LDH, myoglobin), according to a meta-analysis of randomized trials
- A small effect on depressive symptoms across 26 trials (2,160 participants), driven by EPA-rich formulas; DHA-rich ones did nothing
- Well tolerated: across 11 trials and 120,643 patients, no more bleeding than with a placebo, and 1 g per day for over 5 years did not increase serious adverse effects
Precautions
Atrial fibrillation: in major cardiovascular trials (81,210 people followed for nearly 5 years), omega-3s increased the risk by 25%, and by 49% above 1 g per day; a trial of purified EPA at 4 g per day also saw more hospitalizations for fibrillation or flutter. Bleeding: no more than with a placebo across 11 trials, except with high-dose purified EPA (relative risk +50%, or +0.6% absolute) — if you take anticoagulants, talk to your doctor. Also good to know: as a supplement, 1 g per day followed for 5 to 7 years in adults or diabetics, and 4 g per day in high-risk individuals on statins, did not reduce cardiovascular events, and a meta-analysis of 20 studies finds no fewer heart attacks, strokes, or deaths. In healthy adults, no clear effect on lean mass or strength, and the effect on muscle soreness is too small to feel.
Recommended dosage
1 g per day of EPA + DHA in large prevention trials; 2 g or more for blood pressure and muscle after 60 years of age; 3.4 g to lower triglycerides.
How to take it
- For the heart: do not expect protection from them — neither 1 g per day followed for 5 to 7 years (adults, diabetics), nor 4 g per day in high-risk individuals on statins reduced cardiovascular events.
- For blood pressure: systolic drops starting at common doses, diastolic especially from 2 g per day of EPA + DHA; the effect is clearest in untreated hypertensives.
- For triglycerides: 3.4 g per day for 8 weeks lowered them by 27%; 0.85 g per day changed nothing, and neither dose altered cholesterol or inflammation.
- For muscle after 60 years of age: above 2 g per day, +0.67 kg of muscle mass on average; walking speed improves especially in trials lasting longer than 6 months.
- For muscle before 60 years of age: a 2026 meta-analysis finds no clear effect on lean mass or strength in healthy adults (very low-quality evidence); a 10-week weight training trial finds only more strength on the bench press.
- For mood: formulas with at least 60% EPA, at 1 g per day or less, helped with depression; for preventing it, 31 trials probably find no effect.
- For muscle soreness: a drop of 0.93 points out of 10, below the threshold considered noticeable (1.4 points), and nothing on strength or flexibility.
Did you know?
A purified form of EPA (icosapent ethyl), at 4 g per day in patients on statins with high triglycerides, reduced cardiovascular events (17.2% vs 22.0% on placebo over nearly 5 years) — whereas EPA + DHA mixtures, at both 1 g and 4 g per day, made no difference in other major trials.
What the studies say
This meta-analysis examined omega-3 supplementation for fat-free mass and muscle strength in healthy adults. The results showed no clear evidence that omega-3s improve these parameters compared to a placebo. The quality of the evidence was very low, indicating that current data are insufficient to conclude such benefits.
Silva AMF, Simões MO, Artioli GG. — Nutrition (Burbank, Los Angeles County, Calif.) (2026) — 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