Omega-3 Fish Oil: EPA, DHA, and What the Numbers Actually Mean
Omega-3 supplements are one of the most purchased in the UK — and one of the most misread. The label confusion around fish oil is genuine and widespread, and worth clearing up before you buy, because "3000mg fish oil" means something quite different to "3000mg EPA+DHA".
What Omega-3 Fatty Acids Are
Omega-3s are polyunsaturated fats the body cannot produce in sufficient quantities and must obtain from diet or supplementation — making them genuinely essential. The three main forms relevant to human health are ALA (alpha-linolenic acid, found in plant foods), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) — the latter two found in fatty fish and marine sources.
The body can convert ALA to EPA and DHA, but the conversion rate is very low — under 5% for EPA and under 0.5% for DHA in most people. This is why marine-derived EPA and DHA are considered the most physiologically relevant forms for supplementation.
EPA and DHA — What Each Does
DHA contributes to the maintenance of normal brain function and normal vision at 250mg per day. It's a structural component of the brain, retina and cell membranes throughout the nervous system. EPA and DHA together contribute to normal heart function at 250mg per day combined. These are authorised EU health claims reflecting consistent research findings.
The two aren't interchangeable — they have different distributions in the body and different physiological roles. A product that's high in one but low in the other isn't the same as one with a balanced EPA/DHA profile.
How to Read an Omega-3 Label
This is where most people get tripped up. Fish oil is not 100% EPA and DHA. Standard fish oil concentrate is typically 30–50% EPA+DHA by weight — the rest is other fatty acids. So a capsule labelled "1000mg fish oil" might contain only 300mg of combined EPA+DHA.
What matters on the label:
- EPA content — listed in mg per serving
- DHA content — listed in mg per serving
- Total fish oil — the headline figure, but not what you're actually supplementing
Our Omega-3 Fish Oil 3000mg provides 1500mg EPA and 750mg DHA per serving — 2250mg of active EPA+DHA from 3000mg of fish oil concentrate. That's a high-strength dose clearly labelled.
Who Tends to Take Omega-3
- People with low oily fish intake — the main dietary source of EPA and DHA
- Those interested in brain and cardiovascular health at the levels where authorised claims apply
- Older adults, where DHA's role in maintaining normal brain function is particularly relevant
- Pregnant women — DHA supports normal foetal brain and eye development (though a specific prenatal formulation may be more appropriate)
The Bottom Line
Omega-3 is one of the more evidence-supported supplements available — but only if you're actually getting meaningful amounts of EPA and DHA, not just a large headline fish oil figure. Check the label for EPA and DHA separately, and make sure the numbers add up to something worth taking.
Health Leads Omega-3 Fish Oil 3000mg — 1500mg EPA, 750mg DHA per serving. High-strength and clearly labelled. Made to our additive-free standard since 1998. View product →