ketoconazole is a drug that was originally approved as an antifungal, however, over time it showed that it has antiandrogenic properties. It is not absorbed systematically, and different studies have shown that it stops the progression of androgenetic baldness.
In particular, a Japanese clinical study showed that the application of ketoconazole cream 2%, once a day, stops the progression of androgenetic baldness and even reverses part of it.

Put a thin layer of the cream all over the scalp. IF you use minoxidil or another lotion, first apply the lotion and then the ketoconazole cream.

two tubes should easily last  1 month.