Omega-3 (Fish Oil)

Established Supplementsrecovery Last reviewed 2026-09-24

Summary

Long-chain omega-3 fatty acids (EPA/DHA) with a robust, dose-dependent triglyceride-lowering effect. Large modern trials found little or no cardiovascular or mortality benefit from standard supplementation in general populations.

Mechanism

EPA and DHA incorporate into cell membranes, displace arachidonic acid, and give rise to less-inflammatory signaling mediators (resolvins, protectins). They reduce hepatic VLDL-triglyceride production and have antiarrhythmic and endothelial effects.

Reported effects

Ratings are relative to peers in the same category, not absolute claims.

Triglyceride lowering★★★★☆Robust, dose-dependent: ~25-30% reduction at ~4 g/day EPA+DHA.

Ischemic events in high-risk hypertriglyceridemia★★★☆☆REDUCE-IT: 4 g/day icosapent ethyl reduced the primary composite (HR 0.75) — a prescription EPA drug, not standard fish oil.

Major cardiovascular event prevention (general population)★☆☆☆☆Cochrane 2020 and VITAL found little or no effect on mortality, CV events, or stroke.

Studied dosing — research context

Primary-prevention trials typically use around 1 g/day of EPA+DHA; 2-4 g/day is used for triglyceride lowering; REDUCE-IT used 4 g/day of icosapent ethyl (a prescription EPA product). These are doses used in research, not guidance.

Research context only. This is not a recommendation.

Safety

Fishy aftertaste or burps and gastrointestinal upset are common. Prolonged bleeding time occurs at high doses. REDUCE-IT showed an increased atrial fibrillation signal and more serious bleeding with high-dose icosapent ethyl.

Limitations

Early positive trials predate modern statin therapy and may not generalize. EPA-only and EPA+DHA effects appear to differ. REDUCE-IT's mineral-oil placebo may have inflated the treatment effect — a genuine methodological controversy.