Flip over any fish oil label and you'll see two numbers: EPA and DHA. They're related, but they're not interchangeable. Here's the plain-English breakdown.
Written by Vita Globe Editorial Team | Reviewed against NIH Office of Dietary Supplements guidance and peer-reviewed research
What's the difference between DHA and EPA?
Both are long-chain omega-3 fats found mainly in fish and seafood[1]. DHA is a structural fat, concentrated in the brain, retina and sperm, and it builds up in a baby's brain during the third trimester[1]. EPA is best known as a starting material for signaling molecules called eicosanoids[1]. A typical 1,000 mg fish oil provides about 180 mg EPA and 120 mg DHA[1].
Caveat: Many pregnancy trials tested EPA and DHA together, so it's hard to say how much each one alone contributed to the results[2].
Sources: NIH ODS (omega-3) · Cochrane 2018 · Verified 2026-09-27
In this article
Where do DHA and EPA fit in the omega-3 family?
There are three main omega-3s. ALA (alpha-linolenic acid) comes from plants such as flaxseed, soybean and canola oils, chia seeds and walnuts. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) come mainly from fish and seafood[1].
ALA is the only one that's essential in the strict sense, meaning your body can't make it. Your body can convert some ALA into EPA and then DHA, but the conversion is very limited, with reported rates under 15%[1]. That's why EPA and DHA from food or supplements get so much attention.
What does DHA do?
DHA is mainly a building material. It's especially high in the retina, brain and sperm[1], where it's part of cell membranes.
That's why DHA is the omega-3 you see highlighted on prenatal labels. DHA accumulates most rapidly in a baby's brain and retina during the third trimester[1]. Expert consensus recommends that pregnant and breastfeeding women aim for at least 200 mg of DHA a day[3].
What does EPA do?
EPA is more of a messenger. Omega-3s like EPA are used to make eicosanoids, signaling molecules involved in processes such as inflammation. Eicosanoids made from omega-6 fats are generally more potent drivers of inflammation than those made from omega-3s[1].
EPA also shows up often in heart-health research. For a broader look at what omega-3s can and can't do, see Omega-3 Benefits: What the Research Actually Supports.
Which matters more in pregnancy?
DHA gets the headline role because of its place in the brain and eyes. But many of the trials behind the preterm birth findings used combinations of omega-3s, not DHA alone. The 2018 Cochrane review pooled trials of omega-3 supplements and found fewer preterm and early preterm births overall[2], rather than singling out DHA or EPA as the one active ingredient.
The practical takeaway: look at the DHA amount first on a prenatal label, but don't worry if EPA is there too. Fish naturally contains both. Farmed salmon, for example, has about 1.24 g DHA and 0.59 g EPA per 3-ounce serving[1].
The honest summary
- DHA is structural, EPA is a signaling precursor[1].
- DHA is the one highlighted for pregnancy[3].
- Many pregnancy trials used EPA and DHA together[2].
- ALA from plants isn't a reliable swap[1].
How to read DHA and EPA on a label
Supplement labels often list "fish oil" as a total, then EPA and DHA underneath. The total isn't the useful number. Look at the EPA and DHA lines specifically. A typical 1,000 mg fish oil provides about 180 mg EPA and 120 mg DHA[1], so 1,000 mg of fish oil doesn't mean 1,000 mg of omega-3s.
| DHA | EPA | ALA | |
|---|---|---|---|
| Main sources | Fish, seafood, algal oil | Fish, seafood | Flax, chia, walnuts, canola and soybean oils |
| Main role | Structural (brain, retina) | Signaling (eicosanoids) | Plant omega-3; limited conversion to EPA/DHA |
| Pregnancy guidance | At least 200 mg/day (expert consensus) | No separate target | AI of 1.4 g/day |
Algal oil is the main vegetarian source of DHA, usually providing around 100 to 300 mg[1]. If you eat fish, the FDA and EPA suggest 8 to 12 ounces a week of lower-mercury seafood in pregnancy[4].
Side effects of omega-3 supplements are usually mild, like an unpleasant taste, bad breath or heartburn[5]. Tips for that are in Fish Oil Gummies and Fishy Burps.
Our option
Vita Globe Prenatal Fish Oil Gummies
Our Prenatal Fish Oil Gummies pair omega fatty acids from fish oil with vitamins that include folic acid (vitamin B9), in a raspberry and lemon chewable gummy. Suggested use is 2 gummies once daily; they're gluten-free, non-GMO and made without artificial colors or flavors. Check the Supplement Facts panel for the DHA and EPA lines rather than the total. The exact DHA, EPA and folic acid amounts are on the Supplement Facts panel on the product page, so bring it to your OB or midwife. It contains fish, and it isn't a substitute for a prenatal vitamin your provider has recommended.
Frequently asked questions
Is DHA or EPA better for pregnancy?
DHA gets the focus because it's built into the baby's brain and eyes[1], but many pregnancy trials used both[2]. A product with both is fine.
Is DHA the same as omega-3?
DHA is one type of omega-3. EPA and ALA are the others[1].
Can I get DHA from flaxseed?
Flax provides ALA, which your body converts to DHA only in small amounts[1].
What ratio of EPA to DHA should I look for?
There's no official ratio. In pregnancy, most guidance focuses on getting at least 200 mg of DHA a day[3].
Is krill oil better than fish oil?
Krill oil provides omega-3s mainly as phospholipids rather than the forms in fish oil[1]. Evidence that it works better in pregnancy is limited.
Sources
- NIH Office of Dietary Supplements. Omega-3 Fatty Acids: Fact Sheet for Health Professionals. Updated September 20, 2026. ods.od.nih.gov
- Middleton P, Gomersall JC, Gould JF, Shepherd E, Olsen SF, Makrides M. Omega-3 fatty acid addition during pregnancy. Cochrane Database Syst Rev. 2018;11:CD003402. doi:10.1002/14651858.CD003402.pub3
- Koletzko B, Lien E, Agostoni C, Böhles H, Campoy C, et al. The roles of long-chain polyunsaturated fatty acids in pregnancy, lactation and infancy: review of current knowledge and consensus recommendations. J Perinat Med. 2008;36(1):5-14. doi:10.1515/JPM.2008.001
- U.S. Food and Drug Administration and U.S. Environmental Protection Agency. Advice about Eating Fish: For Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years. Updated March 5, 2024. fda.gov
- National Center for Complementary and Integrative Health. Omega-3 Supplements: What You Need To Know. Updated November 2024. nccih.nih.gov
About the Vita Globe Editorial Team
The Vita Globe Editorial Team researches and writes our wellness content, working from peer-reviewed research, systematic reviews and guidance from bodies such as the NIH and the FDA. We cite our sources inline and update articles when the evidence changes.
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. This article is for informational purposes only and is not a substitute for medical advice. Talk to your healthcare provider before starting any new supplement, particularly if you are pregnant, nursing, taking medication, or caring for a child.
