Finasteride is a widely recognized prescription medication used to treat male pattern baldness, known medically as androgenetic alopecia. This treatment works by addressing the hormonal cause of hair thinning, helping to slow the progression of hair loss. However, many people who begin taking the medication encounter a seemingly contradictory experience: an initial period of increased hair fall. This temporary phenomenon, often called “finasteride shedding,” can be confusing and alarming for new users who are expecting to see immediate improvement. Understanding the biology behind this phase is crucial for patients to remain consistent with their treatment plan.
Finasteride’s Influence on the Hair Growth Cycle
Male pattern baldness involves the hormone dihydrotestosterone (DHT). DHT is a potent androgen created when the enzyme 5-alpha reductase converts testosterone. This hormone targets genetically sensitive hair follicles on the scalp. Over time, DHT causes the hair follicles to miniaturize, producing progressively thinner hairs until they eventually stop growing. Finasteride functions by inhibiting the activity of the type II 5-alpha reductase enzyme, which significantly reduces the amount of circulating DHT in the body, often by more than 70%.
This reduction in the hormone’s levels lessens the destructive effect on the hair follicles, allowing them to potentially recover. Hair growth occurs in a cycle with four main phases:
- Growth (anagen)
- Regression (catagen)
- Resting (telogen)
- Shedding (exogen)
By reducing DHT, finasteride helps to shift the balance of the hair cycle, encouraging more follicles to enter the active growth phase.
The medication essentially resets the cycle for many of the weakened, miniaturized hairs. This process forces the existing, older hairs in the resting or early growth phases to be expelled prematurely. This shedding makes room for the new, healthier hair strands that the newly revitalized follicles are starting to produce.
The Reality of the Temporary Shedding Phase
The initial increase in hair fall, known as finasteride shedding, is a temporary event that indicates the medication is actively working. This shedding is the physical manifestation of the hair follicles transitioning back into a healthy growth pattern. The older, weaker hairs are being pushed out by the emerging new hairs, which are expected to be thicker and stronger.
The timing of this shedding phase is relatively consistent, typically beginning a few weeks to a couple of months after starting the treatment. While some individuals may notice it as early as two weeks, it most commonly becomes visible between the second and third months of daily use. The duration of this shedding is also finite, usually lasting for a period of a few weeks up to three months.
This hair loss is not a sign of the underlying condition worsening but rather a sign of the hair cycle correcting itself. After the shedding stabilizes, new hair growth often begins to become visible, with improvements in hair density sometimes observed as early as six months into treatment. Remaining consistent with the daily medication during this unsettling period is necessary to achieve the long-term benefits.
Distinguishing Normal Shedding from Concerns
While temporary shedding is a normal part of the finasteride process, it is helpful to recognize when the hair loss might be more than the expected transition. The normal amount of daily hair fall is typically between 50 and 100 hairs, and finasteride shedding can temporarily cause this amount to double. If the hair fall seems extremely severe or continues without any sign of slowing down, it may warrant a consultation with a healthcare provider.
If the increased shedding persists continuously beyond the three- to four-month mark, it is advisable to seek medical advice. Prolonged or extreme hair loss may suggest that another underlying cause is contributing to the thinning. Concerns should also be raised if the user experiences unexpected side effects, such as changes in libido or mood, which should always prompt a discussion with the prescribing physician. The full benefits of finasteride often require six to twelve months of consistent use to become noticeable.