How do you know this? Any evidence you can provide? Anecdotally on Reddit and hair forums – you read hundreds of posts of people “sprouting new mini hairs” (ie at the hairline), after starting finasteride, minoxidil, and more recently – dermarolling. These hairs may not necessarily be fully miniaturized – but they certainly are thinner than other terminal hairs.
I have seen patients with significant miniaturization placed on finasteride and then upon re-examining them, I saw less miniaturization as hair seem to become thicker in the same areas I examined.