This analysis of 13 studies with 1,752 women found that evening primrose oil performed no better than placebo, topical NSAIDs, vitamin E, or danazol for reducing breast pain. The good news: it's safe and doesn't cause more side effects than placebos. Bottom line—if you're taking EPO for breast pain relief, the evidence suggests you're not getting extra benefit from the ingredient itself.

Researchers reviewed published clinical trials comparing evening primrose oil to placebos or other treatments for breast pain, then pooled the results together to see the overall pattern across studies.

Funding not disclosed in abstract