Propecia's effects in detail:
- Propecia (and other products containing finasteride) causes a rise in testosterone levels, because testosterone that would normally be converted into DHT remains testosterone. Continual high levels of testosterone in the body could possibly have negative side effects.
- Artificially low levels of DHT in the body could cause some unwanted conditions. DHT is an antagonist of estrogen. Men’s bodies also produce the female hormone estrogen in the adrenal glands, although this is just one-tenth of the estrogen that premenopausal women produce in their ovaries. By reducing DHT with drugs, a man’s protection from the effects of estrogen may also be reduced. This could result in gynecomastia.
- Even though both finasteride and dutasteride were developed to combat benign prostatic hyperplasia by reducing DHT in prostate tissue, some scientists question the wisdom of using these 5-alpha reductase inhibitors in younger men who have no problem with their prostates. A research chemist, Patrick Arnold, says “Evidence is mounting that the existence of a high estrogen/androgen ratio – a condition common in older men – is highly correlated with the development of benign prostatic hyperplasia. However, in apparent contradiction, individuals with 5-alpha-reductase deficiency (and thus a similar hormonal profile to users of DHT inhibitors) do not experience BPH.