Omega-3 (EPA + DHA)
The fatty acids your brain and heart depend on.
Omega-3 fatty acids EPA and DHA reduce chronic inflammation, lower triglycerides, and support brain structure throughout life. Large cohort studies consistently link higher omega-3 blood levels with reduced cardiovascular mortality and slower cognitive decline. The Framingham Heart Study found that participants in the top quartile of DHA levels had a 47% lower risk of developing dementia.
How Omega-3 affects aging
EPA and DHA are the raw material for resolvins and protectins — specialized molecules whose job is to actively switch off inflammation once it has done its work. Without enough omega-3, inflammatory responses smolder on instead of resolving, feeding the chronic low-grade inflammation ("inflammaging") that underlies cardiovascular disease, neurodegeneration, and most other age-related conditions. This is why higher omega-3 status consistently tracks with lower CRP and IL-6, two key inflammatory markers.
DHA is also a structural fat: it makes up a large share of the fatty acids in neuronal membranes, where it keeps synapses fluid and functional. Blood omega-3 levels — measured as the Omega-3 Index, the share of EPA and DHA in red blood cell membranes — reflect what your brain and heart tissue actually get. On the cardiovascular side, EPA and DHA lower triglycerides, modestly reduce blood pressure and resting heart rate, and stabilize cell membranes against arrhythmia.
The longevity evidence has recently become more direct. In the DO-HEALTH trial, one gram of omega-3 daily measurably slowed several epigenetic clocks — DNA-methylation measures of biological age — in older adults over three years. And across 17 prospective cohorts, people with the highest circulating omega-3 levels lived meaningfully longer than those with the lowest, regardless of the cause of death examined.
Dosage
RDA: 250-500mg combined EPA and DHA daily (AHA recommendation)
Optimal for longevity: Longevity researchers suggest 1,000-2,000mg combined EPA and DHA daily, targeting an Omega-3 Index of 8-12%.
Food first: two to three servings of fatty fish per week (salmon, sardines, mackerel, herring) covers the basics and brings protein, vitamin D, and selenium along. If you supplement, aim for 1,000–2,000mg of combined EPA and DHA daily. Triglyceride-form fish oil is absorbed better than the cheaper ethyl-ester form; either way, take it with your fattiest meal of the day. Algae oil delivers EPA and DHA directly for vegans — flaxseed (ALA) does not meaningfully convert.
Quality and freshness matter more with fish oil than with most supplements: oxidized (rancid) oil smells fishy and loses benefit. Look for third-party tested products, store them cool and dark, and consider testing your Omega-3 Index — the target zone for longevity is 8–12%, and most people start below 4%.
Deficiency signs
~68% of Americans have an Omega-3 Index below 4%, considered high risk
- Dry, flaky skin
- Difficulty concentrating or brain fog
- Joint stiffness and pain
- Mood changes or low mood
Top food sources
What the research shows
Pooling 42,466 people followed for a median of 16 years, those in the highest quintile of circulating omega-3 had 15–18% lower risk of death from all causes than the lowest quintile — with similar patterns for cardiovascular, cancer, and other mortality. Blood levels, not just intake, predict lifespan.
In 777 adults aged 70+, one gram of omega-3 daily for three years slowed biological aging across several epigenetic clocks (PhenoAge, GrimAge2, DunedinPACE) by up to four months — and combining omega-3 with vitamin D and exercise worked additively.
The honest counterweight: in 25,871 generally healthy adults, 1g of omega-3 daily did not reduce major cardiovascular events or cancer overall. Benefits concentrated in people with low fish intake — supporting a "correct the deficiency" model rather than "more is always better."
Frequently asked questions
Is eating fish better than taking fish oil?
Generally yes — fatty fish delivers EPA and DHA plus protein, vitamin D, and selenium in one package, and trials show clearer benefits from fish than from capsules. Supplements are the fallback for people who rarely eat fish.
How much EPA and DHA should I get daily?
The AHA baseline is 250–500mg combined EPA and DHA. Longevity researchers typically suggest 1,000–2,000mg daily — roughly what it takes to move an Omega-3 Index from the typical 4% into the protective 8–12% range.
Do flaxseed and chia count as omega-3 sources?
Only partially. They provide ALA, which the body converts to EPA and DHA at rates well below 10%. For meaningful EPA/DHA on a plant-based diet, algae oil is the reliable source.
When and how should I take fish oil?
With your fattiest meal of the day — absorption improves substantially with dietary fat. If fishy burps bother you, freeze the capsules or choose enteric-coated, third-party-tested oil (fresh oil barely smells).
Is fish oil safe if I take blood thinners?
At typical doses (up to ~1g daily) fish oil is safe for most people, but at higher doses it has mild blood-thinning effects. If you take anticoagulants or face surgery, discuss dosing with your doctor first.
Track your omega-3 (epa + dha) intake
Biohack logs omega-3 (epa + dha) alongside 22 other longevity nutrients in every meal.