# Can daily omega-3 supplementation reduce your risk of cardiovascular events? > High-dose purified EPA can reduce cardiovascular events in people with existing heart disease, but standard doses of mixed omega-3s show no clear benefit for most healthy adults. By The Editors · Eat · Published 2026-11-03 Canonical: You might find a bottle of fish oil on your kitchen counter or in a supplement aisle. The labels often promise heart health or a boost to your longevity. But when you look past the marketing, the science behind taking these oils every day tells a much more complicated story. For some, the evidence is clear and strong. For others, the benefit is not there at all. To understand why, we have to look at how different studies measured success and who was actually participating in them. ### What the large trials found Most people take omega-3s, which are fatty acids found in marine life, as a way to protect their hearts. However, large studies in people without established heart disease have not shown a clear benefit from standard doses. In the VITAL trial, which followed over 25,000 adults at usual risk, taking 1 gram per day of combined EPA and DHA (two common types of omega-3s) did not reduce the risk of major cardiovascular events like heart attacks or strokes \[1\]. A similar result was seen in the ASCEND trial. In that study, which included people with diabetes but no existing heart disease, 1 gram per day of these fatty acids also failed to reduce the risk of serious vascular events or death from any cause \[2\]. ### A different result for high-risk groups The story changes when you look at people who are already at high risk. In the REDUCE-IT trial, researchers looked at patients already on statins (medications used to lower cholesterol) who also had high levels of triglycerides (a type of fat in your blood). Those in this group who took 4 grams per day of a purified form of EPA (icosapent ethyl) saw a 25% relative reduction in the composite of cardiovascular death, nonfatal heart attacks, nonfatal strokes, coronary revascularization (a procedure to reopen a blocked artery), or unstable angina (chest pain that signals a heart attack may be close) \[3\]. The researchers found that this benefit remained consistent regardless of whether a patient's baseline triglyceride levels were above or below 150 or 200 mg/dL \[3\]. ### The complexity of EPA and DHA While purified EPA showed promise in high-risk settings, the types of omega-3s you take might matter. A large meta-analysis of 38 randomized controlled trials, involving nearly 150,000 participants, found that omega-3s were associated with modest reductions in cardiovascular mortality and heart attacks \[4\]. However, the data suggested a distinction in how these benefits appeared. The reductions were larger for trials using EPA alone than for those using a combination of EPA and DHA \[4\]. This may help explain why some large trials like VITAL and ASCEND showed no benefit, while the REDUCE-IT trial, which used a high dose of purified EPA, did \[3\]\[4\]. ### Safety signals and considerations There are also signals regarding safety that you should be aware of. When researchers pooled data from those same 38 trials, they found a statistically significant increase in the risk of incident atrial fibrillation (a type of irregular heartbeat) among those taking omega-3s \[4\]. While this signal appeared stronger in trials using EPA monotherapy \[4\], at least one individual trial's AF substudy did not find a statistically significant increase. The same meta-analysis found EPA-only formulations significantly increased total bleeding risk \[4\]. While one specific trial of purified EPA found that serious bleeding was only modestly more frequent than placebo, the difference was not statistically significant \[3\]. ### What we still do not know The evidence is not a straight line. We know that high doses of purified EPA can reduce cardiovascular events in high-risk, secondary-prevention patients \[3\]. We also know that standard 1-gram doses of mixed EPA and DHA have not shown the same effect in healthy or primary-prevention populations \[1\]\[2\]. The evidence discussed here is based on trials from 2018 to 2021; while newer analyses exist, they were not included in this review. It remains unclear if the benefits seen in high-dose trials are due to the specific formulation of the supplement or simply the much higher dose itself. While we see signals for increased risk of irregular heartbeats and bleeding, the exact magnitude and significance of these risks can vary depending on the study and the definition of the event used. One secondary analysis of the VITAL trial suggested a larger benefit for Black participants, a finding its own authors called unexpected and not something to act on. Finally, none of the major primary trials demonstrated a benefit in reducing death from any cause. The most consistent positive findings relate to preventing nonfatal ischemic events in people who already have high cardiovascular risk. Because omega-3 supplements can affect heart rhythm and bleeding risk, you should talk with your doctor before changing your supplement routine, especially if you take medication or have a pre-existing condition. As you look at that bottle of fish oil on the kitchen counter, remember that the science behind it is more complex than the label suggests. ## Sources 1. Manson JE et al., New England Journal of Medicine, 2019 (VITAL trial) 2. ASCEND Study Collaborative Group, New England Journal of Medicine, 2018 (ASCEND trial) 3. Bhatt DL et al., New England Journal of Medicine, 2019 (REDUCE-IT trial) 4. Khan SU et al., EClinicalMedicine, 2021 (meta-analysis) --- From suber.health. This is general information, not medical advice. Quote with a link to the article.