Omega-3 for women: benefits, dosing and who needs it
An evidence-based guide to omega-3 for women. What EPA and DHA do, how much you need, food versus supplements, and who actually benefits from taking them.
Reviewed by Emma Carter, Senior Health & Nutrition Editor
Omega-3 is one of the few supplements with a genuinely strong evidence base, but the label hides an important detail: not all omega-3 is the same. What matters for your heart and brain is EPA and DHA, the forms found in fish, and most people get far too little of them.
The three omega-3s that matter
Omega-3 is a family of fats your body cannot make in useful amounts, so you have to eat them. Three matter, and the difference decides whether a supplement is worth taking.
| Type | Where it comes from | What it does |
|---|---|---|
| EPA | Oily fish | Heart, blood vessels, inflammation |
| DHA | Oily fish | Brain, eyes, pregnancy; also the heart |
| ALA | Flax, chia, walnuts | Converts to EPA and DHA only in small amounts |
When a study reports benefits for the heart or brain, it is almost always EPA and DHA being tested, not ALA. The reason matters if you eat mostly plants: the body converts ALA into EPA and DHA poorly, with typical conversion under 5% for DHA and around 5 to 10% for EPA (Foods, 2025). For context on amounts, the American Heart Association points to about 0.5 g a day of EPA plus DHA, and the large trials used around 1 g a day (Foods, 2025).
What it does for women
EPA and DHA support several systems: your heart and blood vessels (helping lower triglycerides), inflammation, your brain and mood, and your eyes, where DHA is a major part of the retina. In pregnancy, DHA is needed for a baby's developing brain and eyes.
The clearest, most consistent benefit is for heart health and triglycerides. Dose does the work here: a meta-analysis found only intakes above 1 g a day of EPA plus DHA reduced cardiac death, major cardiovascular events and heart attacks, by 35, 24 and 33 percent respectively, and EPA alone looked stronger than the EPA-plus-DHA combination for events and heart attacks (Pharmacological Research, 2020). That is prescription territory rather than a general-wellbeing dose, so it is a conversation for your doctor if you have heart risk. Claims for mood, joints and skin are more mixed and depend heavily on dose. Oily fish is also a cornerstone of an anti-inflammatory diet.
How much you need
There is no single official target, but common guidance lands around 250 to 500 mg of combined EPA and DHA a day, roughly two servings of oily fish a week. Pregnant and breastfeeding women are usually advised to add about 200 mg of DHA on top, since the baby draws on the mother's supply. People with high triglycerides are sometimes prescribed much larger doses under medical supervision.
Food first, then who should supplement
The best source is oily fish. A serving of salmon, sardines, mackerel, herring or trout delivers EPA and DHA directly, along with protein and nutrients a capsule does not carry. Two servings a week covers most people. Plant sources such as flax, chia and walnuts give you ALA, still worth eating, but do not count on them to raise your EPA and DHA much.
A supplement earns its place if you:
- Rarely or never eat oily fish
- Follow a vegan or vegetarian diet
- Are pregnant or breastfeeding and not meeting DHA targets
- Have been advised to lower high triglycerides
Vegans have a clean option: algae-based omega-3, the original source fish get it from. Check the label for the actual EPA and DHA amounts, not just total fish oil, since a large-sounding capsule can hold surprisingly little of the active fats.
Safety and when to see a doctor
Omega-3 is well tolerated. The usual complaints are a fishy aftertaste, mild reflux or loose stools, often eased by taking capsules with food or freezing them. Higher doses can thin the blood slightly.
Speak to your doctor before starting high-dose omega-3 if you take blood-thinning medication, have a bleeding disorder, or are managing high triglycerides, so the dose is matched to your needs rather than guessed from a label. Choose a product that lists EPA and DHA per serving and has been tested for purity.
Frequently asked questions
What does omega-3 do for women?
The two active omega-3s, EPA and DHA, support heart and blood vessel health, help regulate inflammation, and are needed for the brain and eyes. DHA is especially important in pregnancy for a baby's brain and eye development.
How much omega-3 do women need?
There is no single official EPA and DHA target for the general population, but many guidelines suggest around 250 to 500 mg of combined EPA and DHA a day for adults, roughly two servings of oily fish a week. Pregnant and breastfeeding women are advised to get extra DHA, often about 200 mg on top.
Should I get omega-3 from food or a supplement?
Food first. Oily fish such as salmon, sardines and mackerel give you EPA and DHA directly along with protein and other nutrients. A supplement makes sense if you rarely eat fish, follow a vegan diet, or are pregnant and not meeting DHA targets.
Can vegetarians and vegans get enough omega-3?
Plant foods like flaxseed, chia and walnuts provide ALA, which the body converts to EPA and DHA only in small amounts. Vegans who want reliable EPA and DHA can use an algae-based supplement, which is the source fish get it from in the first place.
References
- Omega-3 polyunsaturated fatty acids supplementation and cardiovascular outcomes: do formulation, dosage, and baseline cardiovascular risk matter? · Pharmacological Research, 2020
- Omega-3 fatty acids: fact sheet for health professionals · NIH Office of Dietary Supplements
- The role of omega-3 and omega-6 polyunsaturated fatty acid supplementation in human health · Foods, 2025