The cleanest, most-replicated, most-cost-effective hair-loss drug ever — the Kaufman 1998 + 2002 long-term trials show ~65% of men maintain or regrow at 1 mg/day vs ~25% on placebo, sustained at 5 and 10-year follow-up. But: PFS (post-finasteride syndrome) — a small minority of users report persistent sexual dysfunction, mood, and cognitive symptoms that do not resolve after discontinuation. Whether PFS is mechanistically distinct, psychogenic, pre-existing, or rare-real depends on which lit review you read. The honest answer is: the absolute incidence is low (likely <1%, possibly <0.1%) but the persistence is unpredictable, the mechanism plausible (5α-reductase makes neurosteroids including allopregnanolone, important for GABA-A tone), and there is no recovery treatment if it happens. Verdict: WATCH-LIST for Dylan because at 20 with no MPB onset there is nothing to treat. Flips to STRONG (topical first, oral second) if visible MPB onset; flips to SKIP-PERMANENT if family history of psychiatric reactions to 5ARIs or if Dylan-specific risk-aversion to even-low-probability irreversible-mood-or-libido outcomes. Topical 0.25% finasteride solution reduces systemic absorption substantially while delivering similar scalp DHT suppression — preferable first try if hair-loss treatment becomes indicated.