DHA
An omega-3 fatty acid that's a major structural fat in the brain and eyes.
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What it is
DHA is one of the two main long-chain omega-3s (alongside EPA). It's a key structural component of the brain, nervous system, and retina, which is why it's emphasized for cognition and pregnancy. It comes from fatty fish and algae. See our full omega-3 guide for the broader picture.
How it works
DHA is a long-chain omega-3 fat that's a major structural component of brain cell membranes and the retina, supporting the fluidity and signaling those tissues depend on. During pregnancy and infancy it's laid down rapidly in the developing brain and eyes, which is why it's emphasized in prenatal nutrition. (See our omega-3 guide for the broader picture, since DHA usually comes with EPA.)
What it's been studied for
Taken to support brain and eye development in pregnancy and infancy, and cognition across life.
What the evidence shows
A Cochrane review found omega-3 in pregnancy reduced the risk of early preterm birth, and DHA supports fetal brain and eye development. For adult cognition the evidence is mixed, with benefits mainly at higher doses in early or mild decline.
Who should consider it
It's emphasized for pregnant and breastfeeding people (for fetal and infant brain and eye development) and studied for cognition across life. People who don't eat fish are the clearest candidates, and vegans can use algae-derived DHA. It's often taken as part of a broader omega-3 or prenatal product.
Amounts commonly studied
Prenatal guidance commonly targets around 200-300 mg of DHA per day; general omega-3 doses are higher and combine EPA and DHA.
How to take it
Prenatal guidance commonly targets around 200-300 mg of DHA per day; general omega-3 doses are higher and combine EPA and DHA. Take it with a meal containing fat for absorption. Algae oil is the vegan DHA source and is common in prenatal products. Choose products tested for purity.
Forms & absorption
Available in fish oil (with EPA) or as algae oil, a vegan DHA source often used in prenatal products.
Food sources
Oily fish (salmon, sardines, mackerel, herring) are the richest sources; algae is the vegan source. Some eggs and dairy are DHA-fortified. Plant ALA from flax and walnuts converts to DHA inefficiently.
Safety & interactions
Well tolerated. In pregnancy, choose products tested for purity (low mercury) and confirm with your OB or midwife.
Myths & what it won't do
Myth: DHA supplements make babies or adults smarter. Reality: DHA is essential for development and adequate intake matters, but supplements haven't been shown to boost intelligence beyond meeting needs. Myth: plant ALA (flax, chia) covers your DHA. Reality: the body converts ALA to DHA very poorly, so a direct fish or algae source is more reliable.
Common questions
- Do I need DHA if I take fish oil?
- Most fish oil already contains DHA alongside EPA — check the label for the DHA number. A separate DHA product is mainly used in pregnancy or for vegan (algae) DHA.
- Is algae DHA as good as fish?
- Yes — algae is actually where fish get their DHA. Algae oil is a clean, vegan-friendly source that delivers the same DHA.
- How much DHA in pregnancy?
- Guidance commonly suggests around 200-300 mg/day, but confirm the amount and product with your OB or midwife.
The amounts listed here are what published research has used — not a prescription or a recommended dose for you. Confirm anything you plan to take with your own healthcare provider, especially if you take medications, are pregnant or nursing, or have a health condition.
Related goals
Research on DHA
Recommendations on this page are informed by published research. This is educational information, not medical advice.
- Middleton P, Gomersall JC, Gould JF, et al. Omega-3 fatty acid addition during pregnancy. Cochrane Database Syst Rev. 2018;(11):CD003402. View study →
- Shahinfar H, Yazdian Z, Avini NA, et al. A systematic review and dose-response meta-analysis of omega-3 supplementation on cognitive function. Sci Rep. 2025;15(1):30610. View study →Note: The evidence is mixed — benefits appear mainly at higher doses and in early or mild cognitive decline, with little effect in advanced disease.