The natural androgen DHT is a metabolite of testosterone. It is a selective androgen because, unlike testosterone, it cannot be converted to estrogens. It is also a potent androgen, binding to receptors more avidly than testosterone. DHT has an effect on several target tissues, including external genitalia, prostate and skin. DHT deficient men have normal muscle mass and are not osteoporotic. In normal men, DHT supplements suppress pituitary FSH and LH secretion, likely causing infertility. As an androgen, DHT is relatively “prostate sparing.” Because of its potency and potential, significant research is being conducted with DHT supplements for androgen replacement.