Given the estrogen-like effects of red clover isoflavones, concerns have been raised regarding the potential feminization of men following supplementation. However, this is not supported by current evidence. Supplementation with isoflavones (from soy or red clover) for up to 1 year has not been found to affect hormone levels in men, including testosterone, estrogen, or sex hormone binding globulin.[1]
While red clover is sometimes supplemented in men for prostate health, there is currently no convincing evidence to support this use.