Whether finasteride is safe to use at the age of 20?

It is best to discuss your issues with your doctor.  All medications have side effects. You need to also understand Internet is not the best source for personal medical advice.

If you are a candidate for hair loss treatment the medication can help and is safe is used appropriately.  It has the potential of preventing prostate cancer long term.  I suggest you speak to an expert.  Best, Dr. Emer.

shahshil13496,Thanks for the question. There are pro and con to everything in life. The Pro of using finesteride in a young male person with significant hair loss is that it is a very effective in slowing or stopping hair loss in 90%. It can re-grow hair in the crown area in 26%. With regard to the safety of Propecia, in the phase III trial the number of patients in the finesteride 1 mg F(#945) and placebo P(#934), the incidence of decreased libido F (#17/1.8%) whereas P(#12/1.3%). With regards erectile dysfunction F(#12/1.3%) and P(#7/.7%). With regards ejaculatory dysfunction F(#11/1.2%) and P (#7/.7%). The incidence of decreased ejaculatory volume F(#8/.8%) and P(#4/.4%).The total sexually related side effects F(#36/3.8%) and P(20/2.1%). The number of patients that discontinued participation in the study F(#11/1.2%) and P(#8/.9%). Hope this helps.Sincerely,Bernardino A. Arocha, MD

The effects of finasteride on hair loss patients (men) seem to be variable and difficult to predict. Our minds are subject to suggestions regarding the effects of anything we ingest. The most I can tell you is to read as much as possible from reliable sources and then decide if you yourself a trial of usage is prudent. I have many patients who have used finasteride for many years without difficulty. I also have patients who develop problems and elect to stop medication. There is often uncertainty about whether or not the medication is causing problems or is it psychological. I have NO patients that I know of that have suffered permanent harm from finasteride. I also have many patients who have experienced marvelous results for their hair without any detrimental effects.

Many of the points your physician raises are correct. Finasteride can cause side effects in about 1-2 % of users although side effects do tend to be less in men under 40 than those over 40.Side effects include thise you have outlined including impotence, decreased libido, ejaculation problems as well as issues like mood changes gynecomastia. It is believed that most side effects are temporary. However, some men have reported long lasting side effects even when the drug is stopped.  Keep in mind that finasteride is not a 6 month treatment. It's a lifelong treatment. 

The incidence of ED and sexual side effect in men with the use of finasteride is between 2-4%. If you try the drug and get these sexual side effects, you can stop it. Finasteride is VERY effective for treating hair loss in 20 year old men.