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Oenothera biennis (Evening Primrose Oil)

A biennial herb that grows to about 1 meter in height. The oil extracted from the seed contains about 60-80% linoleic acid plus 8-14% gamma-linolenic acid. Uses: Current uses: 1) premenstrual syndrome (especially mastalgia) 2) atopic dermatitis 3) diabetic neuropathy 4) rheumatoid arthritis 5) hot flashes (menopausal symptoms)* 6) mastalgia * not useful [6] Dose: 1) 500 mg capsules 2) 3 g/day commonly used 3) optimal dose not known Adverse effects: 1) nausea 2) softening of stools 3) headache 4) may increase risk pregnancy complications [7] Drug interactions: - may increase risk of bleeding when used with warfarin [7] Mechanism of action: 1) active ingredients: gamma-linolenic acid 2) patients with atopic dermatitis may be deficient in conversion of linoleic acid to gamma-linolenic acid 3) the 1-series of prostaglandins formed using gamma-linolenic acid as substrates may have less inflammatory properties than the 2-series

General

pharmaceutical herb; medicinal herb; herbal supplement; botanical

References

  1. Victoria Rand, UCSF Fresno Lecture, 10/7/98
  2. Budieri et al, Controlled Clinical Trials, 1996
  3. Pye et al, Lancet 1985
  4. Berth-Jones et al, Lancet 1993
  5. Morse et al, British J Dermatology, 1989
  6. Prescriber's Letter 9(9):52 2002
  7. Medical Knowledge Self Assessment Program (MKSAP) 18, American College of Physicians, Philadelphia 2018

Component-of

bilberry/flax oil/oenothera biennis bilberry/oenothera biennis gamma linolenate/oenothera biennis linoleate/oenothera biennis