1 day: Finasteride begins to take effect, preventing the creation of DHT, lowering DHT levels, and starting to build up in your body.
1 week-3 months: While Finasteride "resets" the hair development cycle, at first it will cause your hair to fall out. This is transient and a sign that the medicine is working.
3-4 months: You should begin to notice the effects of finasteride in around three to four months. Your hair loss may slow down, and in some circumstances, it may even stop.
9-12 months: By this time, Finasteride's full impact will be apparent. If you've been taking the medication consistently, you should have noticed a halt in hair loss even if the treatment doesn't improve your hairline or hair thickness.