Finasteride can alter the anagen phase of hair growth, but the length of hair depends upon the genetic hair cycle that you have. Hair grows at 1/2 inch per month on average when there is no balding present. Miniaturized hairs can be maintained or partly reversed to normal, but they will grow slower, not necessarily longer, because the length is ingrained in the mechanics of your hair cycle. Miniaturized hairs will never grow as fast as non-miniaturized hairs nor reach the length of non-miniaturized (Terminal) hairs.