Omega-3 EPA & DHA: What They Actually Do for Your Heart, Brain and Triglycerides

You've probably been told to "take fish oil" at some point — by a doctor, a friend, or something you half-read online. But here's what almost nobody mentions: the two omega-3s inside that capsule, EPA and DHA, do quite different things in your body, and the dose matters far more than the brand on the bottle. If you've ever wondered whether your omega-3 is actually doing anything — or which benefits are real and which are marketing noise — this is the honest, science-led breakdown you deserve.

EPA and DHA Aren't the Same Thing

Omega-3 is an umbrella term. The three you'll encounter most are ALA (found in plants like flax and walnuts), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Your body can technically convert ALA into EPA and DHA — but the conversion rate is genuinely poor. For most adults, it's well under 10%. That's why the marine forms attract all the attention: they're the ones your body can put to work straight away, without the middleman.

EPA and DHA behave more like cousins than twins. EPA tends to be the one researchers reach for when they're studying inflammation, mood and cardiovascular events. It's a precursor to a family of signalling molecules called resolvins and protectins — compounds that help your body resolve inflammation, rather than simply suppress it. DHA, by contrast, is the structural omega-3. It packs into the membranes of your brain cells and the light-detecting cells in your retina, where it makes up a remarkable proportion of the fatty acids present.

So when you read "omega-3 is good for you," what's usually being measured is a combined dose of EPA and DHA. Depending on the ratio and total amount, the effects can look quite different. That nuance is why both dose and composition matter — and why the number on the front of the bottle deserves a second look.

What Omega-3s Actually Do for Your Heart

This is where the science is strongest — and where you should be most sceptical of anyone promising miracles. Here's the honest picture.

Triglycerides — the fats that circulate in your blood after meals — respond reliably to EPA and DHA. Multiple meta-analyses, including a 2025 systematic review across 20 trials and roughly 1,700 participants, show a consistent and statistically significant reduction in triglyceride levels with omega-3 supplementation. The European Food Safety Authority (EFSA) has formally approved the claim that EPA and DHA contribute to the maintenance of normal blood triglyceride levels, with the beneficial effect tied to a daily intake of around 2 g combined.

Heart rhythm and cardiac function are another area with solid backing. EFSA has authorised the claim that DHA and EPA together contribute to the normal function of the heart at a daily intake of 250 mg combined — a much more modest dose. The mechanisms are well understood: omega-3s influence the flexibility of heart cell membranes, affect how ion channels behave, and modestly lower resting heart rate.

Where the picture gets more complicated is in major cardiovascular events — heart attacks and strokes. The recent evidence is genuinely mixed. Some large trials (including the widely cited REDUCE-IT study using high-dose purified EPA) show meaningful benefit; others, like STRENGTH and the 2024 OMEGA-REMODEL trial, don't. The most reasonable current read is that omega-3s reliably move risk factors like triglycerides in the right direction, and may offer real benefit to higher-risk individuals — but they aren't a substitute for the fundamentals: not smoking, staying active, sleeping well and managing blood pressure.

Why Your Brain and Eyes Are Quietly Obsessed With DHA

If you looked at the fats making up the membrane of a brain cell, DHA would be among the most abundant. Your retina is similarly DHA-rich. This isn't coincidence. The structure of DHA makes membranes more fluid and flexible — which matters enormously for the signalling speed of neurons and the light-detecting cells in your eyes.

EFSA has approved two specific health claims for DHA at a daily intake of 250 mg: that it contributes to the maintenance of normal brain function, and that it contributes to the maintenance of normal vision. These aren't marketing positions — they're the outcome of a formal scientific review by an EU regulatory panel that worked through the available human evidence.

DHA's role shifts across the lifespan. During pregnancy and infancy, it's foundational for the developing brain and eye. In adulthood, the focus moves to maintenance — keeping membranes functioning well and supporting cognition through middle and later life. The research on DHA and age-related cognitive decline isn't definitive (nutrition research rarely is), but observational studies and intervention trials repeatedly point in the same supportive direction.

Inflammation: The Quieter Benefit Most People Miss

One of the most consistent findings in omega-3 research is the effect on inflammatory markers. EPA and DHA shift the raw materials your body uses to build signalling molecules — away from the more inflammatory omega-6-derived eicosanoids and towards the calming, resolving family of resolvins and protectins.

In practical terms, supplementation has been shown to reduce circulating CRP (C-reactive protein) and TNF-alpha across many studies. A 2024 meta-analysis in people with rheumatoid arthritis found that omega-3s reduced tender joint counts and improved the omega-6 to omega-3 ratio. None of this makes omega-3 a treatment for inflammatory disease — it isn't — but it does help explain why people taking adequate doses often notice subtle improvements in things like joint comfort and post-exercise recovery.

If you eat a typical Western diet, your omega-6 to omega-3 ratio is probably skewed unfavourably high. Supplementing with EPA and DHA is one of the simpler ways to nudge that ratio back toward something more balanced.

What to Look for in a Supplement

EPA and DHA are two of the most thoroughly studied compounds in nutritional science, and they earn their place in a thoughtful daily routine — particularly if your diet is light on oily fish. They aren't a cure for anything. They are, however, a quietly powerful piece of how your heart, brain and inflammatory system function day to day.

Pick a supplement that tells you the actual EPA and DHA milligrams on the label — not just "1000 mg fish oil," which tells you almost nothing about what's actually inside. Take it consistently with a meal that contains some fat, as omega-3s absorb significantly better alongside dietary fat. And give it a few months. The Omega-3 Index — the measure of EPA and DHA as a percentage of fatty acids in your red blood cells — takes time to shift. So does the rest of your body.

The Compounds at a Glance

• Harmover Omega-3 EPA & DHA Softgels Each softgel delivers 180 mg of EPA and 120 mg of DHA, drawn from fish oil concentrate and stabilised with a small amount of Vitamin E to protect these fragile fatty acids from oxidation. Two softgels daily sits near the 250 mg threshold tied to EFSA's heart and brain claims; four daily moves toward the higher 2 g range associated with triglyceride research. Gentle on the stomach when taken with food.
• EPA (Eicosapentaenoic Acid) One of the two main marine-derived long-chain omega-3 fatty acids. EPA serves as a precursor to specialised pro-resolving mediators — signalling molecules called resolvins and protectins — that help bring inflammatory processes to a clean close rather than letting them linger. It's the omega-3 most strongly associated with cardiovascular research outcomes, including effects on triglycerides, blood pressure and inflammatory markers like CRP.
• DHA (Docosahexaenoic Acid) The structural omega-3. DHA is the fatty acid your body deposits into the membranes of cells that need to be fast, flexible and responsive — most notably brain cells and the photoreceptors of the retina. EFSA has approved health claims for DHA at 250 mg daily for normal brain function and normal vision, and for DHA + EPA combined for normal heart function and normal blood triglyceride levels. DHA is also the omega-3 most associated with foetal and infant brain and eye development.

This article is for informational and educational purposes only and does not constitute medical advice. Harmover supplements are not intended to diagnose, treat, cure or prevent any disease. If you are pregnant, breastfeeding, taking medication or have an existing health condition, please consult a qualified healthcare professional before adding any supplement to your routine.