Evening Primrose Oil (EPO)
Commonly used for
Women's Health
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Wellness uses
PMS and breast tenderness relief, and skin health
This is anecdotal, and there isn't strong clinical evidence that it works for everyone.
What is it? / Overview
GLA is a precursor to anti-inflammatory eicosanoids, and the theory is that PMS and cyclical breast pain reflect an essential-fatty-acid imbalance GLA corrects. In practice, rigorous controlled trials show little clinically significant benefit for most of the traditional uses, despite widespread popularity.
How is it used? / Administration
Form: Oenothera biennis seed oil, standardized to ~8-10% gamma-linolenic acid (GLA)
Typical dose studied: 1-3 g/day (providing ~80-300 mg GLA); benefit, if any, requires 4-6 months
Timing: With food
Systematic reviews of its traditional uses (mastalgia, PMS) are mostly negative -- expect limited benefit.
How well does it work? / Evidence
? Emerging / limited evidence
Who should avoid it?
Avoid with: Breastfeeding; Epilepsy / Seizure disorder; Bleeding disorder / Coagulopathy
Interacts with: Anticoagulants, antiplatelets -- theoretical additive bleeding risk; Drugs that lower seizure threshold (e.g. some antipsychotics) -- case-level concern
Already taking it? Well tolerated (mild GI upset, headache), but the honest read from systematic review is that it's likely ineffective for cyclical breast pain and PMS -- reasonable to continue only if you notice a genuine personal benefit.
Research & references
Bayles B et al. (2009). Evening primrose oil. Am Fam Physician. Sharifi M et al. (2024). The Effect of Oenothera Biennis (Evening Primrose) Oil on Inflammatory Diseases: A Systematic Review of Clinical Trials. BMC Complementary Medicine and Therapies.
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