Topical Finasteride Clinical Trials: Summary of the Evidence
Medically reviewed by [Reviewer Name, MD] | Last reviewed: August 2026 | Editorial policy | Topical finasteride hub
This page summarizes the key clinical trials underpinning the evidence base for topical finasteride. Note: no FDA-approved topical finasteride formulation exists in the US as of 2026; all trials below studied compounded or proprietary formulations.
Trials Summary
| Trial | Design | n | Duration | Key Findings |
|---|---|---|---|---|
| Mazzarella et al., 1997 | RCT; topical fin 0.005% vs. oral fin 1 mg | 20 | 16 weeks | Both groups showed comparable hair growth improvements; topical had lower systemic DHT suppression |
| Caserini et al., 2016 | Phase IIb; topical fin 0.25% spray (LADD technology) | 70 | 24 weeks | Statistically significant hair count improvement; serum DHT reduced ~16% vs. ~72% for oral 1 mg |
| Piraccini et al., 2022 | Phase III; topical fin 0.25% spray vs. placebo; double-blind RCT | 323 | 52 weeks | Statistically superior to placebo on total hair count and scalp coverage; serum DHT reduced ~15–25%; favorable safety profile at study dose |
Evidence Assessment
- The Piraccini 2022 Phase III trial is the largest and most rigorous; it supports efficacy vs. placebo at 52 weeks
- No trial has conducted a powered, long-term head-to-head comparison of topical vs. oral finasteride with 5+ year follow-up
- Formulation standardization is a key limitation: “topical finasteride” encompasses multiple concentrations, vehicles, and technologies; results from one formulation may not generalize to others
Full clinical context: Topical finasteride hub | Topical vs. oral comparison
Sources
- Piraccini BM, et al. “Efficacy and safety of topical finasteride spray solution for male androgenetic alopecia.” J Eur Acad Dermatol Venereol. 2022;36(2):286–294.
- Caserini M, et al. “Effects of a novel finasteride 0.25% topical solution on scalp and serum dihydrotestosterone.” Int J Clin Pharmacol Ther. 2016;54(1):19–27.