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Evening Primrose Oil Side Effects & Safety

Evidence:Moderate
·

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Safety Profile

Overall safety rating: Generally Safe

Potential Side Effects

  • Mild gastrointestinal symptoms (nausea, soft stools, bloating)
  • Headache (uncommon)
  • May increase bleeding time slightly
  • Very rare allergic reactions

Drug & Supplement Interactions

  • May increase bleeding risk with anticoagulants (warfarin, aspirin, NSAIDs) due to antiplatelet effects of GLA metabolites
  • Phenothiazine drugs — EPO may theoretically lower seizure threshold (caution in epilepsy, though evidence is limited)
  • May have additive effects with other anti-inflammatory supplements (fish oil, borage oil)

Maximum Dose

Do not exceed: Up to 6 g/day used in clinical trials without significant adverse effects

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References

  1. RCTMuggli R. (2005). Systemic evening primrose oil improves the biophysical skin parameters of healthy adults. International Journal of Cosmetic Science. DOI PubMed
  2. Meta-analysisBamford JTM, Ray S, Musekiwa A, et al. (2013). Oral evening primrose oil and borage oil for eczema. Cochrane Database of Systematic Reviews. DOI PubMed
  3. Morse NL, Clough PM. (2006). A meta-analysis of randomized, placebo-controlled clinical trials of Efamol evening primrose oil in atopic eczema. Journal of Dermatological Treatment. DOI PubMed
  4. RCTKawamura A, Ooyama K, Kojima K, et al. (2011). Dietary supplementation of gamma-linolenic acid improves skin parameters in subjects with dry skin and mild atopic dermatitis. Journal of Oleo Science. DOI PubMed
  5. Ahmad Adni LL, Norhayati MN, Mohd Rosli RR, Muhammad J (2021). A Systematic Review and Meta-Analysis of the Efficacy of Evening Primrose Oil for Mastalgia Treatment.. International journal of environmental research and public health. DOI PubMed
  6. Moradi M, Niazi A, Heydarian Miri H, Lopez V (2021). The effect of evening primrose oil on labor induction and cervical ripening: A systematic review and meta-analysis.. Phytotherapy research : PTR. DOI PubMed
  7. Meta-analysisKhorshidi M, Zarezadeh M, Moradi Moghaddam O, Emami MR, et al. (2020). Effect of evening primrose oil supplementation on lipid profile: A systematic review and meta-analysis of randomized clinical trials.. Phytotherapy research : PTR. DOI PubMed
Show 5 more references
  1. Budeiri D, Li Wan Po A, Dornan JC (1996). Is evening primrose oil of value in the treatment of premenstrual syndrome?. Controlled clinical trials. DOI PubMed
  2. Horrobin DF, Stewart C (1990). Evening primrose oil in atopic eczema.. Lancet (London, England). DOI PubMed
  3. Meta-analysisLarki M, Mohammadi S, Makvandi S (2025). The Effect of Evening Primrose Oil on Menopausal Symptoms Management: A Systematic Review and Meta-Analysis.. Journal of caring sciences. DOI PubMed
  4. Sharifi M, Nourani N, Sanaie S, Hamedeyazdan S (2024). The effect of Oenothera biennis (Evening primrose) oil on inflammatory diseases: a systematic review of clinical trials.. BMC complementary medicine and therapies. DOI PubMed
  5. Joy CB, Mumby-Croft R, Joy LA (2000). Polyunsaturated fatty acid (fish or evening primrose oil) for schizophrenia.. The Cochrane database of systematic reviews. DOI PubMed