Omega-3 fatty acids (EPA and DHA) are among the most extensively studied compounds in human health research. The evidence base spans cardiovascular disease, inflammation, brain health, eye health, and longevity markers. Despite this, most people who take fish oil are taking the wrong form, the wrong dose, or an oxidized product — and getting little to no benefit.
EPA (eicosapentaenoic acid) is primarily anti-inflammatory. It competes with arachidonic acid for inflammatory pathway enzymes, reduces triglycerides, and has the strongest cardiovascular evidence. The landmark REDUCE-IT trial (2018) showed 4g/day EPA-only supplement reduced major cardiovascular events by 25% in high-risk patients.
DHA (docosahexaenoic acid) is the structural component — it's physically incorporated into brain cell membranes, retinal cells, and heart muscle cells. DHA makes up ~40% of the polyunsaturated fatty acids in the brain. It's critical during development and important for cognitive maintenance in aging.
For longevity: You need both. Aim for a supplement with both EPA and DHA, ideally in a roughly 2:1 EPA:DHA ratio (EPA slightly higher for the anti-inflammatory edge).
Natural fish oil comes in triglyceride (TG) form. Most cheap fish oil is processed into ethyl ester (EE) form for concentration, which is significantly less bioavailable. Re-esterified triglyceride (rTG) oil is concentrated AND converted back to triglyceride form — the best of both.
Look for: "triglyceride form" or "rTG" on the label. Brands like Carlson, Nordic Naturals, and Thorne use rTG form. Take with a fatty meal — omega-3 absorption increases 3x when taken with dietary fat.
View rTG Fish Oil on Amazon →Fish don't synthesize EPA and DHA — they accumulate it by eating microalgae. Algae oil goes directly to the source. Bioavailability is comparable to fish oil, without ocean contaminants (mercury, PCBs), without the fishy burps, and without the sustainability concerns of fish harvesting.
Historically, algae oil was DHA-only. Current products (like Thrive Algae Oil or iwi life) now offer combined EPA+DHA from algae. Slightly more expensive than fish oil but worth the premium for plant-based diets or those sensitive to fish products.
View Algae Omega-3 on Amazon →Krill oil contains omega-3s in phospholipid form and includes astaxanthin (a carotenoid antioxidant). Manufacturers claim superior absorption. The evidence: a 2011 comparison found krill oil was not significantly better absorbed than equivalent-dose rTG fish oil. And krill oil typically contains less EPA+DHA per capsule than fish oil at the same price point.
The astaxanthin is a genuine bonus. But you can buy astaxanthin separately for much less than the premium on krill oil. Don't pay 2x for marketing.
Oxidized fish oil is not just ineffective — it may be harmful. Oxidized lipids generate free radicals that increase cardiovascular risk, potentially counteracting the intended benefit. Studies have found a significant percentage of commercially available fish oil products exceed oxidation safety thresholds. How to check: open a capsule or bite into it. Fresh omega-3 oil should smell faintly of the ocean — not strongly fishy or rancid. If it smells bad, throw it away. Store in the refrigerator after opening.
This is where most buyers go wrong. A bottle labeled "1,000mg Fish Oil" sounds substantial. But the 1,000mg refers to the total oil content — not the EPA+DHA content. A typical 1,000mg fish oil capsule contains only 180mg EPA + 120mg DHA = 300mg combined omega-3. To reach a therapeutic dose (2–4g combined), you'd need 7–13 capsules daily.
Read the Supplement Facts panel. Look at the "EPA" and "DHA" lines specifically, not the total fish oil number. Buy a concentrated product that delivers 500–1,000mg combined EPA+DHA per capsule so you only need 2–4 capsules daily.
| Product | Form | EPA+DHA per serving | Servings to reach 2g | Monthly Cost |
|---|---|---|---|---|
| Nordic Naturals Ultimate Omega | rTG | 1,280mg | 2 caps | ~$35 |
| Thorne Super EPA | rTG | 900mg | 3 caps | ~$38 |
| Carlson Elite Omega-3 | TG | 1,600mg | 1–2 caps | ~$30 |
| iwi life Omega-3 | Algae (TG) | 500mg | 4 caps | ~$40 |
| Generic 1,000mg Fish Oil | EE (usually) | 300mg | 7+ caps | ~$8 |
Omega-3 is Tier 1. Pair it with Vitamin D3+K2, magnesium glycinate, and creatine for the complete evidence-backed longevity foundation.
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