s19m

I am 17 years old and i have been noticing a lot of thinning in my hair recently. after looking into some of the modern day medications such as rogaine and propecia, they seem to speak about hair shedding- a period in which a lot of hair sheds out at once - i cant afford this stage so what i plan to do is shave my head(not bald, like a 2, or 3 for ppl who know the razor lengths) for the 4-6 weeks that the hair will shed. will the hair loss product not work on hair that short?

I am 17 years old and i have been noticing a lot of thinning in my hair recently. after looking into some of the modern day medications such as rogaine and propecia, they seem to speak about hair shedding- a period in which a lot of hair sheds out at once - i cant afford this stage so what i plan to do is shave my head(not bald, like a 2, or 3 for ppl who know the razor lengths) for the 4-6 weeks that the hair will shed. will the hair loss product not work on hair that short?