DHA (omega-3) optimal range and reference range
Compiled by Alina Radu, founder of Sera, from the published sources below · Last reviewed November 9, 2026
Sera's bands for DHA (omega-3):
- Optimal 3 – 8 %; sufficient 2 – 10 %; out of range below 2 or above 10 %.
Evidence grade: Functional / longevity target. A narrower target in common use in functional, integrative, preventive and longevity practice. It is not a universally validated diagnostic range.
At Sera's last range review a change to this band was proposed and held, because the evidence for it was thin, so the band is unchanged. The note below says where it matches published intervals and where it does not.
All units
| Unit | Optimal | Sufficient | Out of range |
|---|---|---|---|
| % | 3 – 8 | 2 – 10 | below 2 or above 10 |
What the evidence says
DHA-specific outcome thresholds are less established than for the Omega-3 Index; the bands reflect functional targets and population distributions rather than a validated cut-off. Slower to shift than EPA, so a low value reflects a longer-standing pattern rather than the last few weeks. No reference interval or guideline threshold exists for red cell DHA as a percentage. In the Framingham cohort the highest fifth, above about 6%, had fewer cardiovascular events and lower mortality than the lowest fifth, below about 3.7%; the optimal band here starts at 3%, inside that lowest fifth.
Assay: Results differ meaningfully between platforms and methods. Compare against the interval printed by the issuing laboratory before acting on a borderline value.
Sources
- Erythrocyte long-chain omega-3 fatty acid levels are inversely associated with mortality and with incident cardiovascular disease: The Framingham Heart Study — Harris WS, Tintle NL, Etherton MR, Vasan RS — Journal of Clinical Lipidology, 2018 · Peer-reviewed publicationFramingham Offspring cohort: red cell DHA fifths were below 3.69%, 3.69 to 4.36, 4.36 to 5.01, 5.01 to 5.96 and above 5.96%. Against the lowest fifth, the highest had a hazard ratio of 0.57 for cardiovascular events and 0.68 for death from any cause. Sera's optimal lower edge of 3% falls in the lowest fifth; the nearest evidenced figure for a favourable level is 5.96%.
- Red Blood Cell Fatty Acid Patterns from 7 countries: Focus on the Omega-3 Index — Schuchardt JP, Cerrato M, Ceseri M, et al. — Prostaglandins, Leukotrienes and Essential Fatty Acids, 2022 · Peer-reviewed publicationMean red cell DHA measured by one method in 17 cohorts: 3.76 to 5.07% in the United States, Canada, Italy and Germany, 6.09% in Spain, and 6.80 to 7.50% in Alaska, Korea and Japan, the cohorts with an Omega-3 Index above 8%. Typical level only, no interval.
- Blood n-3 fatty acid levels and total and cause-specific mortality from 17 prospective studies — Harris WS, Tintle NL, Imamura F, et al. (Fatty Acids and Outcomes Research Consortium) — Nature Communications, 2021 · Peer-reviewed publicationPooled analysis of 17 cohorts, 42,466 people: the highest fifth of circulating EPA, DPA and DHA had 15 to 18% lower all-cause mortality than the lowest. Mixed blood fractions, so it supports the direction and gives no red cell edge.
What DHA (C22:6 n-3, RBC) measures
Docosahexaenoic acid. A long-chain omega-3 fatty acid concentrated in brain and retinal tissue, measured as a share of red blood cell membrane fatty acids.
The structural omega-3: it makes up a large share of the fat in neural membranes, which is why intake matters in pregnancy and through later life. Slower to move than EPA, so a low value reflects a longer-standing pattern.