Omega-3 EPA and DHA for cognition and mood
DHA is a structural brain fat, but supplement trials for memory and mood are mixed, and VITAL found no prevention benefit.
Education only, not medical advice. Talk to your clinician before starting a supplement, especially if you are pregnant, take medication or have a condition.
Evidence grade: C (A strong, B good with gaps, C limited or mixed, D early)
Mood
A 2019 meta-analysis found formulas with at least 60% EPA, at up to 1 g of EPA daily, improved depressive symptoms, while DHA-dominant formulas did not [1]. The 2021 Cochrane review judged the overall effect small and not clearly meaningful, with low-certainty evidence [2]. In VITAL-DEP, 18,353 adults took 1 g of fish oil or placebo for about five years; omega-3 did not prevent depression and was linked to a small increase in risk [3].
Cognition
In 485 older adults with age-related memory complaints, 900 mg of DHA daily for 24 weeks improved a learning and memory test [4]. In people who already have Alzheimer's disease, a Cochrane review found no convincing benefit [5]. VITAL's main trial also found no reduction in cardiovascular events or cancer [6]. We describe omega-3 as supporting normal brain function, not as protection against decline.*
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Sources
- Liao et al. 2019, Transl Psychiatry. doi.org/10.1038/s41398-019-0515-5
- Appleton et al. 2021, Cochrane. doi.org/10.1002/14651858.CD004692.pub5
- Okereke et al. 2021, JAMA (VITAL-DEP). doi.org/10.1001/jama.2021.21187
- Yurko-Mauro et al. 2010, Alzheimers Dement (MIDAS). doi.org/10.1016/j.jalz.2010.01.013
- Burckhardt et al. 2016, Cochrane. doi.org/10.1002/14651858.CD009002.pub3
- Manson et al. 2019, NEJM (VITAL). doi.org/10.1056/NEJMoa1811403
DOIs verified against Crossref and official pages checked on 2026-10-15.