This is an interesting approach to making topical finasteride by using minoxidil to essentially dissolve it into solution as discussed here: https://www.getfreshman.com/learn/can-you-make-your-own-topical-finasteride/
I have no experience with this and do not know if it will work so I can’t give an opinion on it. This link seems to be passing from person to person on the internet. Anyone with experience with it, please contact me.
The traditional compounding pharmacies do not approach it this way. They often create a liposomal formulation which keeps the drug at the skin level and doesn’t let it go into the body. I know that minoxidil is often absorbed into the body from skin applications alone, so I would suspect that the same would occur with finasteride dissolved in the minoxidil solution.