What are the side effects (Other than the ones easily available through literature) of taking something like propecia, rogaine, or saw palmetto when there isn’t any hair loss evident? What I mean is there any extra harm one can do to themselves if they choose to take one as a preventative measure?
As a matter of point, the side effects of taking nothing are less than taking something. Why take a medication that has no proven value for you as a young man? One can make an argument that Propecia can reduce the risks of prostate cancer, although it is not the reason used today to take it in a normal young man. It will not prevent hair loss if you do not have the gene for hair loss.
Paid advertisements (not an endorsement):