Evening Primrose Oil may cause Headaches

Review on April 30, 2009
For many years evening primrose oil has been taken by women suffering from menstrual and menopausal headaches or mood swings. Although there have been limited scientific trials of this natural remedy, many women find that it helps relieve otherwise uncomfortable symptoms. During menopause it can be taken to help calm hormone levels and reduce the likelihood of hot flushes, mood swings and painful headaches.

headaches primrose oilAlthough in some cases headaches during menopause can be caused by symptoms such as lack of sleep, irritability and stress, researchers have made links between these headaches and the increase in estrogen levels in a woman's body during menopause.

Evening primrose oil contains a pain-relieving compound called phenylalanine, hence it being used to treat chronic headaches. However, it is becoming increasingly obvious that excessive use of evening primrose oil may in fact cause headaches and painful migraines.

J Kleijen, who wrote a recent study for the British Medical Journal notes that, ".reported side effects include nausea, softening of the stools, and headache." A trial which was undertaken to establish the best quantity of this supplement for treating menopausal side effects and headaches, tested dosages ranging from two to 16 capsules of 500 mg. A dose of three to six capsules twice a day was found to be the most effective amount for an adult, without causing headaches or stomach pains.

Evening primrose oil has been known to cause seizures in a few cases, and although this is very rare, researchers emphasize the importance of checking with your doctor before you start taking the supplement and not taking it with other strong medicines.


  • SOURCES:
  • Khoo SK, Munro C, Battistutta D. Evening primrose oil and treatment of premenstrual syndrome. Med J Austr 1990;153:189-92.
  • BMJ 1994;309:824-825 (1 October) Kleijnen ,Editorials: Evening primrose oil
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