When the propecia website used to still exist it claimed you MAY start seeing the benefits of the drug as early as 3 months. This was referring more to slowing down shedding and excess loss. However, the actual data from the fda trials showed peak hair counts from 1-2 years on the drug. It’s a slow process. However the 10 year finasteride study made a claim that the first year of treatment would give a good indication of how the drug would work long term for a patient.