With hundreds of products and treatments marketed for hair loss, knowing which ones are actually supported by clinical evidence is one of the most valuable things a patient can learn. Here is a ranking of the major interventions by strength of evidence.
Tier 1 (Strong evidence): Finasteride (oral) — the most evidenced pharmacological treatment for male androgenetic alopecia. FDA-approved. Approximately 83% of users see stabilisation, 66% see some regrowth. Minoxidil (topical) — FDA-approved, shown to promote growth and slow loss. Works best in early to moderate stages. Hair transplant surgery — produces permanent results in appropriate candidates. The standard is outcome, not mechanism.
Tier 2 (Moderate evidence): Dutasteride — more potent than finasteride, approved in some countries for hair loss, used off-label in the UK. Stronger effect on DHT than finasteride but broader side effect profile. Ketoconazole shampoo — some evidence for modest benefit as an adjunct. Low-level laser therapy — evidence of modest benefit as an adjunct in early stage loss.
Tier 3 (Limited or early evidence): PRP therapy — promising early data but insufficient large-scale trials. Saw palmetto — weaker 5-alpha reductase inhibition than finasteride. Caffeine shampoo — interesting mechanism, limited clinical evidence. Collagen supplements — emerging but inconclusive.
No meaningful evidence: Most branded hair loss shampoos, biotin supplementation in non-deficient patients, rosemary oil as a primary treatment, most commercially marketed hair growth serums not in Tier 1 or 2.
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