Finasteride is a prescription medication for male pattern baldness. It slows hair loss and can encourage regrowth in affected areas. The medication helps stabilize hair density over time for many users.
The Role of DHT in Hair Loss
Male pattern baldness is significantly influenced by dihydrotestosterone (DHT). This hormone forms when testosterone interacts with the enzyme 5-alpha-reductase in hair follicles. In genetically predisposed individuals, DHT binds to receptors within hair follicles. This binding initiates miniaturization, causing follicles to progressively shrink. Miniaturized follicles produce hairs that become thinner, shorter, and finer with each growth cycle, eventually ceasing hair production.
How Finasteride Lowers DHT
Finasteride inhibits 5-alpha-reductase, the enzyme converting testosterone into DHT. It primarily targets the Type II isoenzyme, found in hair follicles. By blocking this conversion, finasteride significantly reduces DHT levels in the scalp and bloodstream, often by 60% to 70%. Lowering DHT in the scalp disrupts the hair loss process, creating a favorable environment for existing follicles to recover and for new hair growth.
Hair Follicle Recovery and Regrowth
With reduced levels of DHT circulating in the scalp, hair follicles that have undergone miniaturization can begin to reverse this process. The diminished presence of DHT allows these follicles to enter a healthier anagen, or active growth, phase. This enables the follicles to produce hairs that are thicker, longer, and more pigmented than the fine, wispy hairs characteristic of miniaturization. While finasteride is highly effective at preventing further hair loss by stabilizing existing hair, it can also stimulate regrowth in areas where hair follicles are still viable but have been affected by DHT. The improvement often involves an increase in the number of terminal hairs and a decrease in miniaturized hairs.
What to Expect from Treatment
Individuals beginning finasteride treatment should anticipate a gradual process for observing results, with initial signs like reduced hair loss often noticeable after three to six months of consistent daily use. More significant hair regrowth and increased hair thickness typically become apparent around 12 months into treatment. Results can vary considerably among individuals, and continuous use of the medication is necessary to maintain its benefits. Finasteride is generally more effective at preventing further hair loss and thickening existing hair than at generating new growth in completely bald scalp areas. Some individuals may experience a temporary increase in hair shedding during the first few months as part of the hair cycle adjustment.
Recognizing Potential Side Effects
While finasteride is generally well-tolerated, some individuals may experience side effects. Commonly reported side effects include decreased libido, erectile dysfunction, and ejaculatory disorders. These sexual side effects typically affect less than 1% of users. Less common effects may involve breast tenderness or enlargement. Discuss any concerns or side effects with a healthcare professional before initiating or continuing treatment.