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Do fish oil supplements protect your heart?

What you hear: “Taking fish oil capsules every day protects your heart from attacks and disease.”

What the studies found

In the VITAL trial of 25,871 US adults, 1 gram of fish oil a day for about 5 years did not significantly lower major heart events (hazard ratio 0.92). A Cochrane review of 86 trials (162,796 people) found little or no effect on deaths or heart events overall, with a possible small drop in heart disease events (low-certainty evidence). The exception is a prescription purified form (icosapent ethyl) at 4 grams a day: in 8,179 high-risk people on statins with high triglycerides, events fell from 22.0% to 17.2%. But a similar 4-gram trial of a mixed fish oil drug in 13,078 people was stopped early with no benefit (12.0% vs 12.2%).

Take care: Fish oil supplements raised the risk of an irregular heartbeat (atrial fibrillation) by about 25% across 7 trials, more so above 1 gram a day; in the 4-gram prescription trial, slightly more people had serious bleeding (2.7% vs 2.1%), so people on blood thinners should check with their doctor.

What you could do

Eating oily fish is a fine habit, but don't count on over-the-counter capsules to protect your heart; ask your doctor if you have high triglycerides.

See it in the habit library, with what it means for your own longevity score.

Not medical advice. General information from published studies, not a diagnosis or a treatment plan. Talk with your doctor before starting a supplement or changing a medicine, especially if you are pregnant, take other medicines or have a health condition.

How we judged it

Partly true: Some truth, but oversold as usually said. We judge the claim as it is usually said online, not the habit itself. Trials assign people at random, so they can show cause; observed studies follow people and show a link, not proof. Last checked: October 2026.

The studies, in their own words

1. Manson et al. N Engl J Med 2019 (VITAL omega-3)

   During a median follow-up of 5.3 years, a major cardiovascular event occurred in 386 participants in the n-3 group and in 419 in the placebo group (hazard ratio, 0.92; 95% confidence interval [CI], 0.80 to 1.06; P=0.24).

2. Nicholls et al. JAMA 2020 (STRENGTH)

   The primary end point occurred in 785 patients (12.0%) treated with omega-3 CA vs 795 (12.2%) treated with corn oil (hazard ratio, 0.99 [95% CI, 0.90-1.09]; P = .84).

3. Abdelhamid et al. Cochrane Database Syst Rev 2020

   We included 86 RCTs (162,796 participants) in this review update

4. Bhatt et al. N Engl J Med 2019 (REDUCE-IT)

   A primary end-point event occurred in 17.2% of the patients in the icosapent ethyl group, as compared with 22.0% of the patients in the placebo group (hazard ratio, 0.75; 95% confidence interval [CI], 0.68 to 0.83

5. Bhatt et al. N Engl J Med 2019 (REDUCE-IT)

   Serious bleeding events occurred in 2.7% of the patients in the icosapent ethyl group and in 2.1% in the placebo group (P=0.06).

6. Gencer et al. Circulation 2021

   In meta-analysis, the use of marine ɷ-3 fatty acid supplements was associated with an increased risk of AF (n=2905; HR, 1.25 [95% CI, 1.07-1.46]; P=0.013).

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