A double-blind, placebo controlled study published in Obstetrics and Gynecology (2006; 107(2 Part 1): 247-55) tested the effect of St. John’s wort and black cohosh on menopausal symptoms. The subjects were 301 women with a combination of menopausal symptoms and psychological symptoms (like depression). The women were divided into two groups. One group received a placebo. The other group received a standadized extract obtained from St. John’s wort (containing 250 mcg. of hypericine) and a black cohosh extract (containing 1 mg triterpene glycosides).

The study lasted for 16 weeks. The group taking the herbal supplements took them twice each day for the first eight weeks and once each day for the remaining eight weeks. The group receiving the supplements experienced a 50% reduction of symptoms (according to the Menopause Rating Scale) and nearly a 42% improvement according to the Hamilton Depression Rating Scale. The placebo group experienced 19.6% improvement and 12.7% improvement respectively.