Ingredient evidence
Omega-3
One of the few supplements with a genuine role in pregnancy and cardiovascular health, sold in dozens of products that hide how little EPA and DHA they actually contain.
Also sold as: fish oil, EPA, DHA, algal oil.
Our read of the evidence
Good evidence
Multiple decent human trials point the same way.
Worth taking if you rarely eat oily fish, and genuinely important in pregnancy. Not a mood treatment on its own.
What the evidence actually shows
EPA and DHA are structural and signalling fats the body cannot make efficiently from plant sources. Conversion from ALA, the omega-3 in flax and walnuts, is poor - typically only a few percent - which is why a plant-based diet without algal oil usually runs low.
In pregnancy and breastfeeding, DHA supports fetal brain and eye development, and intake in the UK is frequently below recommendations because of understandable caution about fish. Algal DHA solves this cleanly for anyone avoiding fish.
For heart health, high-dose prescription EPA has trial evidence in specific high-risk groups. Ordinary over-the-counter doses do not deliver the same, and the general-population data on preventing heart attacks is much weaker than the supplement aisle implies.
For mood, higher-EPA formulations show a modest benefit in depression in some meta-analyses, usually as an add-on rather than a stand-alone treatment. It is a reasonable adjunct, not a replacement for treatment.
How to read the label without being misled
A capsule advertising '1,000mg fish oil' may contain only 180mg EPA and 120mg DHA. The number that matters is combined EPA plus DHA per daily serving. Cheap products often need four or five capsules to reach what a good one delivers in one.
Triglyceride-form oils are somewhat better absorbed than ethyl ester forms, though the practical difference is small if you take them with a fatty meal. Look for evidence of purity testing for heavy metals, and a sensible use-by date - oxidised fish oil tastes rancid and is not worth taking.
How to take it.
- Typical dose
- 250-500mg combined EPA + DHA daily for general health
- Form
- Fish oil, cod liver oil or algal oil (vegan)
- Timing
- With a meal containing fat, to aid absorption
- Worth knowing
- Pregnancy: aim for at least 200mg DHA daily, and avoid cod liver oil because of its vitamin A content. Higher therapeutic doses should be a clinical decision.
What it will not do.
- It will not replace treatment for depression
- It will not offset an otherwise poor diet
- It will not prevent heart disease at standard supplement doses in low-risk people
- It will not work if the product contains almost no EPA or DHA - check the label
Who should avoid it.
- You are pregnant and considering cod liver oil - the retinol content is unsafe in pregnancy
- You have a fish or shellfish allergy - use algal oil instead
- You are on anticoagulants and taking high doses without discussing it
Raise with a prescriber
- May add to the effect of anticoagulant and antiplatelet medicines at high doses
- Can slightly lower blood pressure, relevant if you already take antihypertensives
Products containing omega-3.
Everything below is stocked in the UK. Compare on the active dose and the cost per day rather than the size of the pack.
| Product | Key actives | Form | Price | Per day | Best for |
|---|---|---|---|---|---|
| Pregnacare MaxVitabiotics | Folic acid 400ug, Vitamin D 10ug, DHA omega-3 | Tablets + capsules | ~£30 | - | Trying to conceive or already pregnant, Anyone who wants folic acid, vitamin D and DHA in one pack |
| Wild Nutrition Pure Strength Omega 3Wild Nutrition | EPA, DHA | Softgel | £44.00 | £1.47 | Period pain, Low oily fish intake |
| Wellwoman MaxVitabiotics | Omega-3 EPA/DHA, Iron, B vitamins | Tablets + capsules | ~£20 | - | Women who do not eat oily fish, Anyone consolidating several supplements |
| Wild Nutrition Endo SupportWild Nutrition | Magnesium, B vitamins, Botanical blend | Capsule | £46.50 | £1.55 | Nutritional support alongside specialist care |
| DR.VEGAN Vegan Omega 3DR.VEGAN | Algal EPA, Algal DHA | Capsule | £29.99 | 100p | Period pain, Low oily fish intake |
| Bare Biology Life & Soul Omega-3 Daily CapsulesBare Biology | EPA, DHA 1,700mg combined | Softgel | £32.95 | - | Period pain, Low oily fish intake |
| ARTAH Essential OmegasARTAH | EPA, DHA | Capsule | £32.00 | £1.07 | Period pain, Low oily fish intake |
| Together Health Algae Omega 3Together Health | Algal DHA, Algal EPA | Softgel | £17.95 | 60p | Period pain, Low oily fish intake |
| Igennus Vegepa EPA with Evening Primrose OilIgennus Healthcare Nutrition | EPA, GLA from evening primrose oil | Softgel | £15.95 | 53p | Period pain, Low oily fish intake, Cyclical breast tenderness, as a trial |
| Igennus Vegan Omega-3 Algae OilIgennus Healthcare Nutrition | Algal DHA 400mg, Algal EPA 200mg | Softgel | £22.95 | 77p | Period pain, Low oily fish intake |
Prices are the brand's UK list price at the time of writing and change often. Cost per day is calculated from pack size and the label's daily serving, and is shown only where both are published.
Common questions.
How much omega-3 should I take a day?
For general health, 250-500mg of combined EPA and DHA daily if you rarely eat oily fish. In pregnancy, aim for at least 200mg DHA.
Is algal oil as good as fish oil?
Yes. Algae are where fish get their EPA and DHA in the first place. Algal oil is the right choice for vegans, vegetarians and anyone with a fish allergy.
Can I take omega-3 in pregnancy?
DHA is beneficial in pregnancy, but avoid cod liver oil specifically because of its high vitamin A content. Choose a pregnancy-appropriate fish or algal oil.
Does omega-3 help with periods?
Some small trials suggest omega-3 reduces period pain, possibly through effects on prostaglandins. The evidence is limited but the safety profile is good.
Where this comes from.
A supplement is not clinical care.
If symptoms are affecting your work, your sleep or your relationships, the useful next step is an assessment rather than another purchase. Our check-in takes three minutes and points you to the right kind of clinician.
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Good evidence. Vitamin D is a genuine UK public health recommendation. K2 is reasonable, optional and oversold.
Limited evidence. Reasonable to try for cyclical breast tenderness. Unlikely to do anything for hot flushes.
Good evidence. Highly effective when you are deficient. Potentially harmful when you are not. Get tested.
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Food supplements are not medicines and are not intended to diagnose, treat or cure any condition. They should not replace a varied diet or prescribed treatment. If you are pregnant, breastfeeding, taking medication or managing a diagnosed condition, check with a pharmacist or clinician before starting anything on this page. We do not accept payment for inclusion or placement. Where a link earns us a commission we say so on the product page. Last reviewed 27 August 2026.