SO DYK
HEART FUNCTION

Evening primrose

Oenothera biennis

also known as EPO, Evening primrose oil

Moderate (eczema, premenstrual)

A tall North American wildflower whose seeds are pressed for an oil rich in gamma-linolenic acid (GLA) — an essential fatty acid most fats lack. Used by Indigenous peoples for centuries before becoming a popular European supplement in the 1980s. Evening primrose oil is most useful for skin conditions and certain hormone-related discomforts, though some early enthusiasm has not held up.

  • Eases eczema symptoms in some people, particularly itching
  • May ease breast pain that comes with the menstrual cycle (cyclical mastalgia)
  • May ease premenstrual symptoms in some women
  • Source of GLA (gamma-linolenic acid), an omega-6 fatty acid the body uses to make anti-inflammatory signaling molecules
  • Long Indigenous American use of the whole plant for skin and respiratory conditions
  • Topical use of the oil supports dry, irritated skin

Active in Gamma-linolenic acid (GLA), Linoleic acid.

Mild blood-thinning effect — caution with blood thinners
May lower the threshold for seizures — caution with seizure disorders and medications that affect seizure threshold (some antidepressants, antipsychotics)
Stop two weeks before surgery — particularly important for procedures with bleeding risk
Use caution with phenothiazine medications (older antipsychotics)
Skip during pregnancy at high doses — may affect labor, though some midwifery traditions use it differently in late pregnancy
Skip during nursing without provider guidance
Generally well tolerated; mild stomach upset and headache occasionally reported
Effects on eczema and PMS build over weeks to months — not a quick fix