Omega-3 EPA and DHA: What the Science Says

Disclosure: This article contains links to Prolean Wellness products marked as sponsored. | FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Products are not intended to diagnose, treat, cure, or prevent any disease. This article is for general educational purposes only and is not medical advice. Always consult your healthcare provider before starting any new supplement.

The Essential Fatty Acids Most People Don't Get Enough Of

Omega-3 fatty acids are essential — the body cannot synthesize them in adequate amounts and must obtain them from diet or supplementation. The two most biologically active forms are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found primarily in fatty fish, shellfish, and algae.

The problem is that the typical Western diet is dramatically skewed toward omega-6 fatty acids (from vegetable oils and processed foods) and low in the marine omega-3s that human physiology depends on. Estimates from clinical research suggest a large share of the US population has lower-than-optimal omega-3 blood levels based on dietary intake data.

EPA vs. DHA: Different Roles in the Body

While EPA and DHA are often grouped together, they have distinct roles:

• EPA is involved in the body's normal inflammatory response processes. It is the precursor to a family of signaling molecules (resolvins and protectins). EPA is the form more closely associated with cardiovascular and mood-related research.
• DHA is a structural component of cell membranes, particularly concentrated in the brain, retina, and heart. It is important for neurological development and is the dominant omega-3 in brain tissue throughout life.

Both are important, and most clinical trials have studied them together.

A Note on Prescription vs. Dietary Supplement Omega-3s

It's important to distinguish between prescription omega-3 medications and over-the-counter dietary supplements, because research on one does not automatically apply to the other. The REDUCE-IT trial, published in the New England Journal of Medicine, studied icosapent ethyl — a highly purified, FDA-approved prescription drug (not a dietary supplement) — at 4g/day in over 8,000 patients who already had elevated triglycerides and established cardiovascular disease or diabetes. Researchers observed a reduction in a composite of cardiovascular events compared to placebo in that trial. Because of findings like this, prescription omega-3 medications are FDA-approved specifically for treating severe hypertriglyceridemia in certain patients — under a doctor's care.

Dietary supplement fish oil products, including the one described later in this article, are not prescription drugs, are not FDA-approved to treat any disease, and are typically taken at lower doses of EPA/DHA than the doses studied in prescription drug trials. Findings from prescription drug research should not be read as claims about what an over-the-counter supplement will do.

What Researchers Are Studying in General Omega-3 Intake

Triglycerides

This is one of the most consistently replicated findings across omega-3 research generally. Trials have found that higher intakes of EPA and DHA are associated with lower serum triglycerides, with higher doses generally producing larger changes. This general dose-response relationship is part of why prescription-strength, high-dose EPA formulations are used under medical supervision for significantly elevated triglycerides — a different context from typical dietary supplement doses.

Brain Health

DHA makes up approximately 40% of the polyunsaturated fatty acids in the brain. Some epidemiological research has associated higher omega-3 blood levels with markers related to brain aging, though this kind of observational research cannot establish that supplementation causes those outcomes.

The Nuanced Cardiovascular Picture

Not all omega-3 trials have shown the same results, even at the drug level. The VITAL trial, using 1g/day of EPA+DHA, did not significantly reduce the primary cardiovascular endpoints in a general adult population without established cardiovascular disease. The STRENGTH trial, using 4g/day of EPA+DHA (combined, not EPA-only), also did not show a benefit on its primary endpoint. This contrast with REDUCE-IT has generated real scientific debate about the role of form, dose, and patient population — and underscores why results from a prescription drug trial in a high-risk patient group shouldn't be generalized to an over-the-counter supplement used by a general, healthy population.

Who Considers Omega-3 Supplementation

Anyone who does not consume fatty fish (salmon, mackerel, sardines, anchovies) at least twice per week may not be meeting typical dietary omega-3 intake recommendations through diet alone. Vegetarians and vegans who avoid fish entirely may consider algae-based DHA/EPA supplements. Anyone with a diagnosed cardiovascular condition, elevated triglycerides, or other medical condition should work with their healthcare provider on an appropriate, individualized plan — which may include prescription options — rather than relying on an over-the-counter supplement alone.

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What to Look for in an Omega-3 Supplement

• EPA and DHA content: Check the label for actual EPA and DHA milligrams per serving — not just total fish oil. Many products list 1,000mg fish oil but deliver far less combined EPA+DHA.
• Triglyceride form vs. ethyl ester: Triglyceride form omega-3s are generally considered better absorbed than ethyl ester forms.
• Purity and oxidation: Fish oil oxidizes easily. Look for products that include antioxidants (like vitamin E) and are third-party tested for purity and freshness (peroxide value).
• Sustainability: Look for products from fisheries certified by organizations like Friend of the Sea or the Marine Stewardship Council.

The Bottom Line

EPA and DHA are essential nutrients relevant to cardiovascular and neurological health, and many people fall short of typical dietary recommendations. Research on triglycerides is fairly consistent at a general level. Cardiovascular outcome research is more nuanced and, at the highest-dose, most conclusive end, involves prescription medications used under medical supervision — not dietary supplements. For most adults not regularly eating fatty fish, an omega-3 dietary supplement is one option to help close a dietary gap, and any cardiovascular or metabolic concerns are best addressed with a healthcare provider.

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References
1. Bhatt DL, et al. Cardiovascular risk reduction with icosapent ethyl for hypertriglyceridemia (REDUCE-IT). N Engl J Med. 2019. PMID: 30415628
2. Omega-3 fatty acids and cardiovascular outcomes: updated review. PMC. 2024. PMC12628397

FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease. This article is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before beginning any supplement regimen.