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Head-to-head evidence comparison — which supplement is right for you?
Finasteride (topical) vs Sunscreen (SPF): Sunscreen (SPF) has the stronger overall evidence (9 vs 6.5/10); the best pick depends on your goals. Take the 60-second quiz for a pick tailored to your goals.
Sunscreen (SPF) wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Mostly mechanism / observational
Top outcomes
Verdict
Mostly mechanism / observational
Top outcomes
Apply finasteride 0.25% topical solution to the scalp once daily. Lower applied volumes reduce serum DHT less while still cutting scalp DHT substantially.
evening
Finasteride 0.25% topical solution
Topical OTC. Apply a broad-spectrum SPF 30+ sunscreen daily to sun-exposed skin as the last step of a morning routine, using an adequate amount (about 2 mg/cm² — roughly a nickel-sized dollop for the face, a shot-glass for the body) and reapply every ~2 hours of sun exposure and after swimming/sweating. Mineral (zinc oxide / titanium dioxide) filters are preferred if you're concerned about systemic absorption. There is no oral or systemic dose — it is not ingested. This library does not provide an ingestion protocol.
morning
Broad-spectrum SPF 30+, applied daily; mineral (zinc oxide/titanium dioxide) if concerned about absorption
immediate
24 weeks
24 weeks
1 week
Throughout
Ongoing (years)
Ongoing
Throughout
Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia: a phase III, randomized, controlled clinical trial
J Eur Acad Dermatol Venereol (2022) · Rct · n=458
The pivotal trial: phase III, double-blind, DOUBLE-DUMMY, so it compares topical against placebo AND against oral finasteride in the same study.
Effects of a novel finasteride 0.25% topical solution on scalp and serum dihydrotestosterone in healthy men with androgenetic alopecia
Int J Clin Pharmacol Ther (2016) · Rct · n=50
⚠️ THE CAVEAT THAT MATTERS: serum DHT fell 60-70%. "Topical avoids systemic exposure" is not what this study shows at the higher doses.
Comparing the therapeutic effects of finasteride gel and tablet in treatment of the androgenetic alopecia
Indian J Dermatol Venereol Leprol (2009) · Rct · n=45
A direct head-to-head of gel against tablet, double-blind and double-dummy, six months.
Sunscreen and prevention of skin aging: a randomized trial.
Ann Intern Med (2013) · Rct · n=903
Randomized community trial (n=903): the daily sunscreen group showed no detectable increase in photoaging (skin microtopography) after 4.5 years
Molecular mechanisms of photoaging and its prevention by retinoic acid: ultraviolet irradiation induces MAP kinase signal transduction cascades that induce Ap-1-regulated matrix metalloproteinases that degrade human skin in vivo.
J Investig Dermatol Symp Proc (1998) · Review
Mechanistic model: UV activates MAP-kinase pathways and AP-1, which upregulate matrix metalloproteinases (MMPs)
Daily Use of a Facial Broad Spectrum Sunscreen Over One-Year Significantly Improves Clinical Evaluation of Photoaging.
Dermatol Surg (2016) · Open label · n=32
Single-arm prospective study (n=32): broad-spectrum SPF 30 applied daily to the face for 52 weeks
Sunscreen (SPF) has a higher evidence score (9/10 vs 6.5/10) and wins in 3 of 3 categories.
No known interactions between Finasteride (topical) and Sunscreen (SPF) have been documented in our database. However, always consult a healthcare provider before combining supplements.
The right pick depends on your goals. Answer a few quick questions for a personalised recommendation — or dig into the full evidence on each.