Why Would Libido and Breast Side Effects Occur with Finasteride Use?
Dr. Rassman,
Is it unhealthy for a young man with a normal size prostate to take a drug (finasteride) which shrinks his prostate? It seems as though shrinking an organ that is a healthy size is a bad idea?
Also, since propecia actually causes more testosterone to be released in a man’s body, why is breast enlargement (which seems like too much estrogen), and loss of libido, etc a potential side effect? It seems more logical to me that with increased testosterone, a man would have an increase in libido, stronger erections, more ejaculate, more muscle (smaller breasts), etc.. But the reverse side-effects are listed as being caused by finasteride. Could you explain why?
There is no evidence that finasteride (Propecia) shrinks normal sized prostates, but to the best of my knowledge, the prostate size in young men has not been studied. The reason that testosterone levels rise simply reflects the brilliance of the human body, which recognizes that DHT levels are dropping on Propecia so it compensates with increasing the levels of testosterone. Men need a certain level of male hormones and the human body regulates that level by pushing the testicles to make more or less testosterone to achieve those levels. Testosterone levels rise an average of 15-18% when a person is on Propecia, which does increase the sex drive in some men (about 10% in my experience). That happened to me when I started my Propecia, so I know this from personal experience. One possible explanation for the other effects you asked about might show that finasteride might directly antagonize androgen action in breast tissue. If that was the case, it might indirectly increase the estrogen concentration in the body and cause these effects, but this is strictly a guess on my part as there is no evidence for this. I can not explain the other things you asked about. Sorry.
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. Gynecomastia could be one result of this. Gynecomastia is abnormally large breasts in a male.
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, Pat Arnold – “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