When your hair starts fallin' out, there's phases. Denial is usually phase 1. It's followed by some more denial, and then a total freakout. When you start trying to fix it and google "how to stop hair loss", Minoxidil is a top result. It won't ruin your sex life, and it's been around forever. Worth trying, right?
Not really. Before I completely take a crap on your plan, let me explain. What Minoxidil really does is stimulate random hair growth. Minoxidil, the generic name for Rogaine, is a drug originally created as a blood pressure medication. When users started experiencing odd side effects like hair sprouting out of their backs, cheeks, and heads, researchers decided to use minoxidil for people dealing with hair loss.
Put simply, minoxidil doesn't stop hair loss. It stimulates random hair growth, which for some amount of time can cover for the amount of hair lost due to male pattern baldness. Being it never got to the root of the problem, after some time, the amount of hair shed from male pattern baldness can't be covered up by some extra hair growth, and it becomes obvious that minoxidil isn't the miracle you were looking for.
To properly stop hair loss, you'll need to dig deep and stop it at the core i.e. do something about the actual cause. The first step would be to block DHT on your scalp, so as to keep the follicles alive. Step two would be to stimulate hair growth after. By blocking DHT first, you will actively stop your hair loss, and you'll get the results you were looking for.