Omega-3 fatty acids found in fatty fish or in supplements are among the most extensively studied nutrients for heart health, brain function, and overall well-being. For most people, a daily fish oil capsule is beneficial and safe for the long term.

You May Get Heart Health Benefits

Omega-3s, particularly EPA and DHA, are most often associated with heart health. Research shows that long-term daily omega-3 supplementation can lower the risk of heart attack and death from coronary heart disease, especially in people who eat little fish and have two or more risk factors of heart disease.

For people with established heart disease or very high triglyceride levels, higher doses of EPA may offer additional protection against serious cardiovascular events.

However, not all research has confirmed this benefit, and these effects may not apply to standard over-the-counter fish oil supplements.

While omega-3s are widely recognized for supporting heart health, their effects can vary depending on dose, formulation, and individual risk factors.

You May Improve Cholesterol and Metabolic Health

Research indicates that long-term omega-3 supplementation can help lower triglycerides, particularly at doses exceeding 2 grams per day.

In fact, higher doses may reduce triglycerides by 50–57 mg/dL in people with metabolic syndrome or elevated triglyceride levels.

That said, LDL cholesterol may rise slightly, especially with lower doses, and effects on HDL cholesterol, blood pressure, or glucose metabolism tend to be inconsistent.

You May Support Brain Health

People often take omega-3s for brain health, but the evidence on their long-term effectiveness is mixed.

DHA, in particular, may help support memory and thinking and reduce the risk of Alzheimer’s disease or age-related cognitive decline when taken over time.

Studies show that higher omega-3 intake or blood levels are linked to a lower risk of dementia, especially in people who are at risk or have early signs of cognitive decline. But the benefits appear small, and are usually stronger for those with lower omega-3 levels to start with.

Potential Downsides

For most healthy adults, daily omega-3 supplementation appears to be safe and well-tolerated. Clinical trials and long-term studies generally show few serious side effects.

Mild issues, such as fishy aftertaste, diarrhea, or minor skin changes, are the most common complaints. Importantly, major safety concerns like serious bleeding events or liver damage are rare, even at higher doses used for therapeutic purposes.

While serious adverse events are uncommon, there are a few concerns to be aware of:

• Bleeding risk: Omega-3s can slightly increase the chance of bleeding, particularly at doses above 1–2  grams per day. Serious bleeding events are rare, and most people do not experience major problems.
• Atrial Fibrillation: Some studies have found a small increase in new-onset atrial fibrillation, especially at higher doses.
• Gastrointestinal issues: Mild diarrhea, nausea, and a fishy taste are the most common side effects.
• Laboratory changes: Slight increases in blood sugar, liver enzymes, and LDL cholesterol may occur.

Overall, these risks are usually mild and manageable, particularly at standard doses.

How Much Should You Take?

For general health, most guidelines suggest 250 milligrams of combined EPA and DHA per day, which can easily be met by eating two servings of fatty fish per week. You can also get EPA and DHA from supplements if you don’t eat fish.

Higher doses are recommended for:

• People who are pregnant: Up to 450 mg per day of EPA + DHA.
• People with documented heart disease: 1 gram per day of EPA + DHA.
• Those with high triglyceride levels: 2–4 grams per day, usually under medical supervision.

Doses up to 1 gram per day are generally considered safe for everyone, but up to 4 grams per day can be used therapeutically—though high doses should always be monitored by a healthcare provider.