Androgenetic alopecia (AGA) — pattern hair loss driven by dihydrotestosterone (DHT) sensitivity in genetically predisposed follicles — affects approximately 50% of men and 30% of women by age 50. The pathophysiology is well-understood: DHT-sensitive follicles gradually miniaturize through successively shorter anagen (growth) phases, eventually producing fine vellus hairs that are barely visible before follicular death. The FDA-approved treatment options are limited but effective when started early; newer options including oral minoxidil and microneedling are rapidly accumulating evidence.
Minoxidil: The Topical Standard
Topical minoxidil (2% women, 5% men — though 5% is increasingly used in women) remains the first-line OTC treatment for AGA. Minoxidil's mechanism: potassium channel opener that increases follicular blood flow and may directly stimulate keratinocyte growth factor — extending the anagen phase and reversing miniaturization. Evidence: 5% minoxidil twice daily produces visible improvement (>20% hair count increase) in approximately 60% of men over 12 months in the pivotal RCTs, with maximal response at 12–18 months. Response is maintained only with continued use — discontinuation reverses any gains within 3–6 months.
Oral Minoxidil: The Evidence-Based Off-Label Option
Low-dose oral minoxidil (0.25–1.25mg daily for women, 2.5–5mg daily for men) has rapidly accumulated RCT evidence showing superior efficacy to topical minoxidil with improved compliance (once daily oral vs twice daily topical application). A 2020 JAAD study of 1404 patients found 89% hair density improvement at 1 year. Primary side effects: facial hypertrichosis (body hair growth — dose-dependent), fluid retention, and tachycardia at higher doses. These limit use in women sensitive to unwanted body hair. Low-dose protocols minimize side effects. Oral minoxidil for AGA requires physician prescription and monitoring.
Finasteride and Dutasteride: DHT Suppression
Finasteride (1mg daily) inhibits 5α-reductase type II, reducing scalp DHT by 60% — stopping miniaturization and producing visible hair regrowth in 90% of men after 2 years. Evidence is strongest of any AGA pharmacotherapy for male AGA. Post-finasteride syndrome (persistent sexual side effects after discontinuation) is reported by a subset of users — incidence disputed, but concern has led many dermatologists to counsel patients thoroughly before prescribing. Dutasteride (0.5mg daily) inhibits both 5α-reductase type I and II, reducing scalp DHT by 90% — superior efficacy to finasteride in head-to-head trials, approved for AGA in South Korea and Japan. Both are prescription-only and gender-appropriate (women of childbearing potential: contraindicated due to fetal 5α-reductase inhibition). Healthcare facilities can find relevant skin care products in our catalog.
