Eicosapentaenoic acid (omega-3, EPA)
Omega fatty acidsAlso known as: EPA, fish oil EPA, Omega-3
EPA is a long-chain omega-3 fatty acid mainly found in fatty fish.
It helps regulate inflammation and supports heart and blood vessel health.
Why this matters
Adequate EPA levels are linked to a lower risk of heart disease, better blood lipid levels, and reduced inflammation. Measuring EPA helps you see whether you get enough omega-3s from diet or supplements.
How this connects to other biomarkers
- Eicosapentaenoic Acid is the principal anti-inflammatory long-chain omega-3 and a major component of the Omega-3 Index.
- Low EPA with elevated AA / EPA Ratio and high hs-CRP indicates a pro-inflammatory state amenable to fish-oil therapy.
- EPA is preferentially converted to anti-inflammatory eicosanoids and is associated with reduced cardiovascular events when the Omega-3 Index is > 8%.
How often should I test Eicosapentaenoic acid (omega-3, EPA)?
Most adults benefit from yearly EPA testing as part of a fatty acid panel. After a sustained change in diet or supplementation, retest at 3 to 4 months.
At baseline / for screening: Once every 12 months as part of a fatty acid panel. More frequently, every 3 to 6 months, if you're managing a cardiometabolic concern where fatty acids matter.
When monitoring an intervention or change: Retest 3 to 4 months after a sustained change in dietary fat, such as increasing fatty fish, omega-3 supplements (EPA/DHA), or reducing seed oils. Red cell membranes take this long to fully reflect the new intake. Day-to-day variability is minimal, so only sustained dietary patterns shift the picture meaningfully; don't expect quick changes from short-term diet shifts.
Note: EPA begins rising within weeks of supplementation but takes 3 to 4 months to reach a steady state in red cell membranes. For dose-response tracking, retest at 3 months after each dose adjustment; sooner retests reflect partial uptake rather than the final value.
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