The only chance you have to slow down your MPB is with Fin (although Minoxidil can really help the crown), but it's not certain that your hair loss will progress rapidly. I've spoken to many guys who started losing hair in their twenties (sometimes in their teens) and who made it to their 40s without major progression in their balding pattern.
The crux of the matter is this: MPB is unpredictable. With the medications you do give yourself the best chance of holding on to your hair.
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