Effects of Hypericum perforatum (St. John's wort) on hot flashes and quality of life in perimenopausal women: a randomized pilot trial

Menopause. 2009 Mar-Apr;16(2):307-14. doi: 10.1097/gme.0b013e31818572a0.


Objective: The aim of this pilot double-blind, randomized clinical trial, which initially targeted breast cancer survivors, was to obtain preliminary evidence of the effect of Hypericum perforatum extract (St. John's wort extract) compared with placebo on symptoms and quality of life of symptomatic perimenopausal women. We also assessed practical difficulties in recruiting women to such a trial.

Methods: Symptomatic perimenopausal women aged 40 to 65 years who experience hot flashes (three or more per day, Heart and Estrogen/Progestin Replacement Study scale) were randomly assigned to receive ethanolic St. John's wort extract (900 mg TID) or placebo. The women were asked to keep a daily diary during the week before randomization and during the week before the 3-month follow-up (primary outcome) to record hot flash frequency and intensity. A hot flash score (frequency x severity) was calculated. The Menopause-Specific Quality of Life questionnaire was used to assess menopause-specific quality of life.

Results: Forty-seven women were randomized. After 12 weeks of treatment, a nonsignificant difference favoring the St. John's wort group was observed in the daily hot flash frequency (St. John's wort, -2.3 +/- 3.6; placebo, -1.0 +/- 2.2; P = 0.11) and the hot flash score (-3.8 +/- 8.3 and -1.8 +/- 6.5, respectively; P = 0.10). After 3 months of treatment, compared with the placebo group, women in the St. John's wort group reported significantly better menopause-specific quality of life (P = 0.01) and significantly fewer sleep problems (P = 0.05).

Conclusions: Hypericum perforatum may improve quality of life in ways that are important to symptomatic perimenopausal women, but these results need to be confirmed by a larger clinical trial.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Double-Blind Method
  • Female
  • Hot Flashes / drug therapy*
  • Humans
  • Hypericum*
  • Middle Aged
  • Perimenopause
  • Phytotherapy*
  • Pilot Projects
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use
  • Quality of Life*
  • Treatment Outcome


  • Plant Extracts