The issue regarding testosterone replacement therapy in men, associated with middle age and later, has become increasingly controversial because of the link between testosterone and prostate cancer. This is reminiscent of the association between estrogen and breast cancer in women. However, the two may not be comparable. In men, there seems to be a relationship between dihydrotestosterone (DHT) and prostate cancer. This association was confirmed in recent studies showing that Proscar and Avodart (both of which block the conversion of testosterone to dihydrotestosterone) decrease the incidence of prostate cancer in long-term controled studies. However it is unclear whether testosterone itself is linked to prostate cancer. In a seminal book, Testosterone for Life, by Abraham Morgentaler, the author points out the benefits of testosterone therapy in middle age and older men and debunks the prostate cancer risk. He even shows that low testosterone levels may predispose to prostate cancer. However, he does not answer the question regarding why dihydrotestosterone appears to be a risk factor for prostate cancer. Men suffering from low libido, depression and erectile dysfunction deserve to have a complete evaluation, including measurement of testosterone levels and appropriate pituitary hormones that may influence testosterone levels. If a man is found to have low testosterone levels on repeated testing, replacement therapy may be indicated with a patch or gel as appropriate to that individual.
The issue of testosterone replacement in women is more controversial than that of men because there are no long-term studies of using testosterone replacement therapy in women. The issue of breast cancer is certainly raised and it is unclear what role testosterone may play in either preventing or accelerating breast cancer. Testosterone does appear to influence libido in women as well as men. However, it also stimulates the growth of excess hair on the face, as well as contributing to increased acne. It is often incorporated into hormone replacement preparations. The appropriate dosing in women is unclear, although blood testing is helpful in preventing excess hormone replacement levels.