rightoff replied: "Propecia is the name of the drug Finasteride prescribed in 1mg doses to combat hair loss in men. Propecia side effects include some forms of sexual dysfunction which may alarm some users. The information below is from a study done to show the effects of Propecia. The effects of Propecia and the side effects were noted on 1,553 males who took Propecia over a 2 year period. Clinical trials produced the following statistics for Propecia side effects: Decrease in sexual desire: 1.8% Problems with erection: 1.3% Decrease in semen volume ejaculated: 1.2% To put these figures into perspective, when monitoring Propecia's side effects, 3.8% experienced some kind of sexual dysfunction while 2.1% of the men using a placebo also experienced the same problems. Additionally, these side effects were reversible in the men who discontinued taking Propecia and within some weeks they had disappeared. One point to note is that the stopping of Propecia can result in losing any hair that has been regrown. The drug needs to be taken indefinitely to maintain the hair growth and density. However, if you discontinued taking the drug after experiencing the Propecia side effects noted above, it is very unlikely you would experience any decrease in hair growth. This is because it takes between three to six months of daily use to see any increase in hair growth and the side effects are experienced well before then. As Propecia effects hormone levels some men experienced tenderness in the breast. However, this was a small number and no more than those who used the placebo. This perhaps is the most worrying aspect about Propecia's side effects. The fact that you are young means that you may have to continue taking this drug perhaps for decades for male pattern baldness and to maintain your level of hair growth. Since it was only approved in 1998 no one can really say what all the side effects really are."