tuneTypical Dose
Studied doses vary by product and indication
Fatty Acid
Evening Primrose Oil
Oenothera biennis
Evidence TierDWADA NOT PROHIBITED
watchEffect Window
Trial durations are usually weeks to months.
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
Evening primrose oil has weak evidence for mastalgia and does not work well for eczema, so it should not be treated as a broad anti-inflammatory skin supplement.
Evening primrose oil is another gamma-linolenic-acid supplement with a reputation that exceeds the data. The strongest pooled evidence still suggests little to no meaningful overall effect for mastalgia or eczema. A newer single-center mastalgia trial reported symptom improvement, especially when evening primrose oil was combined with vitamin E, but that does not overturn the broader negative or equivalence-heavy literature.
Evening primrose oil is used as a gamma-linolenic-acid source, but the human efficacy signal is weak across the conditions for which it is usually sold.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Weak evidence for mastalgia
Secondary Outcomes
- No convincing evidence for eczema improvement
Safety
Contraindications and Interactions
Contraindications
- Pregnancy
Side effects
- GI upset
Interactions
- Anticoagulants or antiplatelet drugs
Avoid if
- You want a proven eczema treatment
- You expect strong mastalgia relief from supplement marketing alone
Evidence
Study-level References
epo-SRC-001Systematic review and meta-analysis
Sourceopen_in_newAhmad Adni LL, Norhayati MN, Mohd Rosli RR, Muhammad J. A Systematic Review and Meta-Analysis of the Efficacy of Evening Primrose Oil for Mastalgia Treatment. Int J Environ Res Public Health. 2021;18(12):6295. doi:10.3390/ijerph18126295. PMID:34200727.
Population: Women with mastalgia across randomized clinical trials of evening primrose oil versus placebo or other treatments
Dose protocol: Trial specific across mastalgia studies
Key findings: Across 13 randomized trials, evening primrose oil did not outperform placebo, topical NSAIDs, danazol, or vitamin E for mastalgia relief.
Notes: Best mastalgia summary.
Paper content
This 2021 systematic review and meta-analysis included 13 randomized mastalgia trials with 1752 women. Across placebo and active-comparator studies, evening primrose oil did not show a clear advantage for pain relief over placebo, topical NSAIDs, danazol, or vitamin E. Adverse events such as nausea, bloating, headache, giddiness, weight gain, and altered taste were not increased versus control. The review supports a safety signal but not a strong efficacy signal for mastalgia.
epo-SRC-003Randomized controlled trial
Sourceopen_in_newKumari J, Amrita, Sinha A, Kumari S, Biswas P, Poonam. Effectiveness of Evening Primrose and Vitamin E for Cyclical Mastalgia: A Prospective Study. Cureus. 2024;16(4):e58055. doi:10.7759/cureus.58055. PMID:38752050.
Population: Premenopausal women with cyclical mastalgia
Dose protocol: Evening primrose oil 1000 mg twice daily, vitamin E 400 mg daily, their combination, or placebo for 6 months
Key findings: In a single-center randomized trial, evening primrose oil alone improved cyclical mastalgia versus placebo, but the combination of evening primrose oil plus vitamin E performed best.
Notes: Useful modern add-on because it shows why isolated positive trials should be interpreted against the larger pooled literature rather than in isolation.
Paper content
This randomized mastalgia trial assigned 126 premenopausal women to evening primrose oil, vitamin E, their combination, or placebo for 6 months. The combination arm produced the largest symptom reduction, while evening primrose oil alone and vitamin E alone also improved pain versus placebo. Because the study was single center and the broader mastalgia meta-analysis remains largely negative or equivalent, this paper is better treated as a modern but not definitive positive signal.
epo-SRC-002Systematic review
Sourceopen_in_newBamford JTM, et al. Oral evening primrose oil and borage oil for eczema. Cochrane Database Syst Rev. 2013. doi:10.1002/14651858.CD004416.pub2. PMID:23633319.
Population: Adults and children with eczema from randomized trials of oral evening primrose oil or borage oil.
Dose protocol: Trial specific across eczema studies
Key findings: No meaningful eczema benefit over placebo.
Notes: Best eczema review.
Paper content
This is the main modern evidence anchor for evening primrose oil in eczema. The review found no clinically useful effect and concluded further trials would be hard to justify.