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Evening primrose oil (GLA)

A GLA-rich oil with a big reputation for skin and PMS — and disappointing trial results.

Reviewed by Bodil Isaksson, Licensed Biomedical Scientist (Sweden)Last reviewed July 2026Supplement guide

SupplementsFatty acidsOmega-6Skin

Evening primrose oil is a source of gamma-linolenic acid (GLA), an omega-6 fat once hoped to calm inflammation in skin conditions. The trials, unfortunately, have not been kind.

Key takeaways

  • The active is GLA (an omega-6 fatty acid); borage oil is a higher-GLA alternative.
  • A Cochrane review found neither evening primrose nor borage oil helps eczema.1
  • Evidence for PMS and breast pain is weak and mixed.
  • Generally safe; mild GI upset, and blood-thinning at high doses.

What it is

Oil from evening primrose seeds, notable for its GLA content. The theory was that GLA would boost anti-inflammatory prostaglandins — appealing, but not borne out.

The evidence

The definitive Cochrane review concluded oral evening primrose and borage oils are not effective for eczema, performing no better than placebo.1 Data for premenstrual syndrome and cyclical breast pain are inconsistent and weak.

Dose

Products supply a few hundred mg of GLA; given the weak evidence, expectations should be low. Borage oil offers more GLA but the same limited benefit.

Safety

Well tolerated. Caution with anticoagulants and before surgery; discuss use in epilepsy.

Bottom line: a popular oil that the best evidence simply doesn’t support for eczema, and only weakly for PMS — safe, but likely underwhelming.

References

Adult research summary for education, not a prescription.

  1. Bamford JTM, et al. Oral evening primrose oil and borage oil for eczema. Cochrane Database Syst Rev. www.cochrane.org

This article summarises nutrition science for education. It is not a substitute for individual medical advice; consult a professional before starting a supplement, in pregnancy, or alongside medication.