Effect of black cohosh (cimicifuga racemosa) on vasomotor symptoms in postmenopausal women: A randomized clinical trial. 

This randomized, double-blind, placebo-controlled clinical trial was published in 2013. Researchers recruited 84 postmenopausal women to determine the impact of black cohosh supplementation on vasomotor symptoms such as hot flashes over eight weeks. Authors founds that there was a significant difference between the two groups in terms of severity and number of hot flashes in weeks four and eight.

References:

Shahnazi M, Nahaee J, Mohammad-Alizadeh-Charandabi S, Bayatipayan S. Effect of black cohosh (cimicifuga racemosa) on vasomotor symptoms in postmenopausal women: a randomized clinical trial. J Caring Sci. 2013;2(2):105-113. Published 2013 Jun 1. doi:10.5681/jcs.2013.013 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4161092/