Research
Evening primrose oil for Menopause: Evidence, Interactions and Cautions
Evening primrose oil is an ingredient used in menopause supplements marketed to women. Below is what it has actually been studied for, how strong that evidence is, the drug interactions and cautions on record, and the primary source our grade rests on — all drawn from the HerWellReport ingredient dataset.
Also sold as: Oenothera biennis; EPO; gamolenic acid; gamma-linolenic acid
What the evidence says about Evening primrose oil
The one menopause trial cited by the Menopause Society randomised 56 women to 500 mg of evening primrose oil daily or placebo for six months; hot flushes fell by 1.0 per day on evening primrose oil and by 2.6 per day on placebo, so it did not beat placebo. That is a single small trial, and the handful of later trials are also small and conflicting. The Menopause Society's 2023 nonhormone therapy position statement names evening primrose oil on its not-recommended list (Level II). NCCIH separately states there is insufficient evidence to show whether evening primrose oil helps menopause symptoms.
The grade "very limited for hot flushes; none for stress incontinence" means: very limited — Mostly animal, laboratory or anecdotal evidence, with at most a single weak human study. none — No human trial evidence we could find for this use. Grades are explained in full on our methodology page.
Read the primary source this grade rests on (opens in a new tab).
Evening primrose oil drug interactions
- warfarin and other anticoagulants
- antiplatelet drugs
- lopinavir and other antiretrovirals
- blood pressure medicines
Who should be careful with Evening primrose oil
- Avoid in pregnancy — use has been associated with prolonged rupture of membranes and arrest of descent in labour
- commonly causes abdominal pain, nausea, indigestion and loose stools
Read more on HerWellReport
- Best Menopause Supplements: What Is Actually In Them
- Confitrol24 Review (2026): The Trial Is Real, But the Label Doesn’t Say How Much
- Nature’s Way AM/PM PeriMenopause Formula: An Honest Ingredient Review
- Is It Normal to Pee Every Hour? What Counts as Normal Urinary Frequency
- Why Does My Bladder Still Feel Full After I Pee? Causes in Women, and When It Needs a Doctor
This entry is generated from row "Evening primrose oil" of the HerWellReport ingredient dataset (v2.1, updated 2026-09-23). The dataset is free to reuse under CC BY 4.0 — how to cite it. Ingredient evidence is not evidence for any finished product, and nothing here is medical advice.