I am worried to take Finasteride because I have read that becoming impotent is a possible side effect. Is this true?

Yes, this is a possible side effect, but the risks are extremely low. I suggest seeing a hair loss expert now to evaluate and go over your condition and provide you information about your best treatment options. There are great non-invasive options like prp/progesterone and/or hair transplantation. See an expert. Best, Dr. Emer

Finasteride prevents hair loss by blocking DHT (Dihydrotestosterone )-the primary hormone responsible for hair loss.The major side effect is loss of libido and/or erectile dysfunction-this occurs in 1-2% of users and is generally reversible.

Unfortunately, there is no way to know if this will happen to you. The good news is, the chances are extremely low and this is not a common side effect that men experience from taking Finasteride. 

Impotence is an uncommon side effect of finasteride. The most recent data indicate that 1-2% of male patients may experience this.  This is usually a temporary situation as the body becomes accustomed to the medication.  It's also important to realize that erectile dysfunction is caused by and related to many factors, so sometimes patients may have other issues going on.  It's useful to discuss the pros and cons of any medication with a qualified medical provider.

Yes, it is possible although the risk is quite low. Less than 2 % of males experience sexual dysfunction, including impotence, while using finasteride. There is no good way yet to predict.

Finasteride blocks "a byproduct" of testosterone, not testosterone itself. The byproduct (5-alpha-dehysdrotestosterone) is what causes male pattern hair loss. It is ok to take it if your doctor recommended it. There is no real evidence that this medication causes impotence.