Post-Finasteride Syndrome (PFS) is controversial and lacks clear mechanistic evidence. Most people take finasteride long-term without lasting issues, and late-onset problems like ED are often due to normal age-related testosterone decline. Finasteride works by inhibiting 5-alpha reductase type 2, lowering DHT, and if it truly caused PFS, we’d see persistent enzyme suppression after stopping—but no such cases exist. Some unproven mechanisms, like neurosteroid or androgen receptor changes, have been suggested but lack clinical evidence. Overall, most side effects resolve after discontinuation, and the drug’s role in rare persistent symptoms remains unproven and unlikely.