I don't quite like how many people, such as yourself, warn wholeheartedly against Finasteride. Everyone is entitled to their opinion, but if someone's hair is shedding noticeably off-cycle at an early age, chances are without proper protection they will become bald or close to it very early on in life. There are very few options for these people. In fact, the only other real option for truly preventing or slowing hair loss to any reasonable degree is an unregulated, under-tested substance called RU58841 which lacks real world experience. The side effects of Finasteride are far less common and drastic than some people make them out to be. Often, people just regurgitate the warning comments other people make about Finasteride, without actually trying it for themselves.
The likelihood of permanent damage is COMPLETELY overstated. And frankly, it is a bit of a joke how people seem to care so much about the very rare side effects of Finasteride, while ignoring the fact that almost every drug in the world has rare side effects that are equally disturbing, yet are taken without second thought.