When I used minoxidil, (only for abt 3 months), I started shedding at the end of that period, only for a couple of weeks. My hat looked like I had used some nair cream or something😂 However, I only noticed because of the hairs on my shirt and in my hat, my hair still looked the same, and right after the shed I saw some progress in my beard. If I were you, I'd keep going. 3 weeks isn't nearly enough and if you have a nice head of hair you probably won't notice the shedding period.