Finasteride is the most clinically evidenced oral treatment for male pattern hair loss. Understanding what it does, what results to expect, and what the risks are allows patients to make an informed decision rather than relying on anecdote or marketing.
Finasteride works by inhibiting the enzyme 5-alpha reductase type II, which is responsible for converting testosterone to DHT in the scalp and other tissues. By reducing DHT levels by approximately 70%, finasteride slows or halts the miniaturisation of hair follicles in genetically susceptible individuals.
Clinical trials show that approximately 83% of men taking finasteride experience no further progression of hair loss, and around 66% see some degree of regrowth — particularly in the crown area. Results at the hairline are typically more modest. Finasteride must be taken continuously — stopping causes DHT levels to return to baseline within a few months, and the hair loss that was being suppressed resumes.
Side effects are the most commonly raised concern. The prescribing literature lists sexual side effects — reduced libido, erectile dysfunction, reduced ejaculate volume — in a small percentage of users. The majority of men tolerate finasteride without any sexual side effects. Post-Finasteride Syndrome (PFS) — the persistence of side effects after stopping the medication — is a contested area of research. Patients with concerns should discuss these in detail with their prescribing doctor before starting treatment.
Finasteride is prescription-only in the UK and should not be sourced from unregulated online pharmacies. A reputable supplier will require a medical consultation before prescribing.
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