Briese V, Stammwitz U, Friede M, Henneicke-von Zepelin HH. Black cohosh with or without St. John's wort for symptom-specific climacteric treatment—results of a large-scale, controlled, observational study. Maturitas. Aug 20 2007;57(4):405-414.
A prospective, controlled open-label observational study of 6141 women was used to analyze the effect of Black cohosh alone (Remifemin®) or in conjunction with St. John's wort (Remifemin® plus) on menopausal symptoms. After 3 months, the participants' Menopause Rating Scale (MRS) and PSYCHE scores were determined, demonstrating that the menopause-relieving characteristics of black cohosh were enhanced by St. John's wort. However, because of the observational nature of the study, no placebo-controlled group was included.
Rebbeck TR, Troxel AB, Norman S, et al. A retrospective case-control study of the use of hormone-related supplements and association with breast cancer. Int J Cancer. Apr 1 2007;120(7):1523-1528.
The relationship between breast cancer risk and hormone-related supplement use, including black cohosh, was assessed in a population-based case-control study of 949 participants with breast cancer and 1524 control participants. Use of either black cohosh or Remifemin® was associated with a reduction in breast cancer risk. Future studies to analyze the putative chemopreventative effects of black cohosh are required.
Pockaj BA, et al. Phase III double-blind, randomized, placebo-controlled crossover trial of black cohosh in the management of hot flashes: NCCTG trial N01CC. J Clin Oncol 2006;24:2836-41.
One hundred and thirty-two women with persistent hot flashes for at least one month were randomized to receive 20mg of black cohosh extract twice a day or placebo for four weeks. This was followed by a crossover period of four more weeks where women who initially received black cohosh were given placebo and vice versa. Participants maintained weekly diaries of symptoms including nausea, excessive sweating, chills, headache, nervousness etc. At the end of the study period, women who received black cohosh reported a 20% reduction in the hot flash score compared to a 27% decrease by women on placebo.
These data suggest that black cohosh is not superior to placebo in reducing hot flashes.