Finasteride is a frequently prescribed oral medication for treating male pattern baldness, known medically as androgenetic alopecia. This condition results from a genetic sensitivity that causes hair follicles to shrink over time. A common initial concern for new users is the temporary increase in hair loss, often called the shedding phase. This expected reaction can be unsettling, but it is a normal response that indicates the medication is beginning to work. Understanding the typical timeline of this shedding helps users manage expectations and remain consistent with treatment.
Understanding the Hair Cycle and Finasteride’s Role
Hair growth occurs in a continuous, multi-stage cycle involving growth (Anagen), rest (Telogen), and shedding (Exogen). In male pattern baldness, Dihydrotestosterone (DHT) progressively shortens the Anagen phase and causes hair follicles to miniaturize, leading to finer, shorter hairs.
Finasteride works by inhibiting the enzyme 5-alpha reductase, which converts testosterone into DHT. Reducing DHT concentration removes the hormonal signal that causes follicle miniaturization, resetting the hair growth process.
The shedding phase occurs because the weakened hairs are forced out prematurely as the follicle prepares for a new, healthier Anagen phase. The old, weaker hair must be expelled before the new, stronger hair can grow, causing the noticeable increase in shedding shortly after starting the medication.
Typical Onset and Duration of Finasteride Shedding
The onset of finasteride-induced shedding typically begins within the first month or two of starting treatment. Most users notice increased hair loss between two and eight weeks after beginning daily use, aligning with the period when DHT levels are sufficiently lowered to initiate the hair cycle reset.
The intensity of shedding varies, with some users noticing no change and others experiencing a distinct increase in hair fall. Practical signs include finding more hairs than usual in the shower drain, on a pillowcase, or caught in a brush. This temporary increase in hair loss is a direct biological response to the drug’s action and should not be confused with the progression of underlying hair loss.
The acute shedding phase generally lasts for one to three months. For most users, the rate of hair loss stabilizes and returns to baseline levels by the four to six-month mark of consistent treatment. If intense shedding persists beyond six months, a consultation with a healthcare provider is warranted.
What the Shedding Phase Signifies for Treatment Success
Experiencing the shedding phase is generally interpreted as a positive sign that the medication is actively resetting the growth cycle. The temporary loss of older, weaker hairs confirms the drug is effective in reducing DHT and preparing the follicles to produce thicker, terminal hairs. Users should not view this initial increase in hair fall as a sign of treatment failure.
Following the shedding phase, the hair follicles enter a prolonged, healthier Anagen phase, leading to visible improvements in hair density. New hair growth is typically very fine (vellus hair) at first, but it gradually matures into thicker, pigmented terminal hair. The first signs of new growth are often observed around three to six months after beginning treatment.
Significant aesthetic results usually become apparent between six and twelve months of consistent daily use. Maintaining strict adherence to the treatment schedule is important, as stopping the medication will halt the DHT-lowering effect and reverse any progress made.