Evening primrose oil (EPO) is the primary source of gamma-linolenic acid (GLA), an omega-6 fatty acid that paradoxically has anti-inflammatory effects. Our research shows moderate evidence for diabetic neuropathy (GLA at 480mg/day) and eczema/atopic dermatitis, but the popular use for PMS is NOT supported by rigorous evidence — a 1996 systematic review found it ineffective, and the UK withdrew its pharmaceutical license for this indication. For skin conditions, it takes 4-12 weeks and most studies used higher doses than typical OTC products provide.
GLA from EPO is converted to DGLA (dihomo-gamma-linolenic acid) which produces PGE1 — a prostaglandin with anti-inflammatory, vasodilatory, and immune-modulating properties. This is unusual because most omega-6 fatty acids are converted to arachidonic acid and pro-inflammatory prostaglandins. The delta-5-desaturase enzyme normally converts DGLA → arachidonic acid, but GLA supplementation overwhelms this step, favoring the anti-inflammatory PGE1 pathway. In diabetic neuropathy, GLA restores nerve blood flow and nerve membrane fatty acid composition.
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:
Not medical advice. Based on published clinical research and systematic reviews.