The herbal supplement black cohosh, whether used alone or with other botanicals, did not relieve hot flashes in women in the Herbal Alternatives (HALT) for Menopause Study. HALT, co-funded by NCCAM and the National Institute on Aging, did find that women using menopausal hormone therapy received significant relief from their hot flashes and night sweats.
The year-long, randomized, double-blind trial compared several herbal regimens and menopausal hormone therapy to placebo. The study included 351 women, ages 45 to 55, who were approaching menopause or were postmenopausal. HALT was conducted at the Seattle-based Group Health Center for Health Studies. Each participant was experiencing at least two hot flashes and/or night sweats daily at the study's start.
Researchers found no significant difference between the number of daily hot flashes and/or night sweats in any of the herbal supplement groups compared to the placebo group. After one year, the average difference was fewer than 0.6 symptoms per day. However, the average difference at one year in symptoms between the menopausal hormone therapy and placebo group was significant—4.06 fewer symptoms per day among women receiving hormones.
Newton KM, Reed SD, LaCroix AZ, et al. Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormonal therapy, or placebo: a randomized trial. Annals of Internal Medicine.; 145(12):869–879.2006