Pharmaceutical5-alpha-reductase inhibitorTopicalAnti-androgen

Topical Finasteride

Also known as Topical Propecia · Finasteride spray/gel

Written by enwyReviewed 15 Jul 20261 sources0 comments

Topical finasteride is a scalp-applied formulation of the 5-alpha-reductase inhibitor finasteride, developed to treat androgenetic alopecia with lower systemic DHT suppression than the oral tablet. Trials show comparable scalp DHT reduction and hair benefit with reduced, but not absent, systemic exposure.

01 Overview

Formulated as a solution, gel, or spray, topical finasteride aims to deliver 5ARI action to the scalp while limiting the systemic side effects that drive discontinuation of oral finasteride. A dedicated formulation has gained regulatory attention and some approvals.

Evidence indicates it lowers scalp DHT and improves hair count similarly to the oral drug, with lower serum DHT suppression. However, measurable systemic absorption occurs, so sexual and mood side effects remain possible, and use is contraindicated around pregnancy.

02 Mechanism

Inhibits type II 5-alpha-reductase in the scalp, reducing local conversion of testosterone to DHT and thereby slowing follicle miniaturisation, with intended reduced systemic delivery versus oral dosing.

03 Dosing

Tier	Dose	Route	Notes
Alopecia	0.25 %/day	Transdermal	0.25% solution, ~200 microlitres per scalp application once or twice daily

04 Effects

Effect	Magnitude	Evidence
Improved hair countIncreases target-area hair count with efficacy similar to oral finasteride in trials.	Comparable to oral	Clinical
Lower systemic DHT suppressionSerum DHT falls less than with oral dosing while scalp DHT is still reduced.	Reduced vs oral	Clinical

05 Side effects

Effect	Severity	Frequency	Evidence
Sexual dysfunctionReduced libido or erectile difficulty, less common than with oral but still reported.	Moderate	Uncommon	Clinical
Post-finasteride syndrome (reported)Persistent sexual, cognitive, and mood symptoms reported after discontinuation; causal link debated.	Severe	Rare	Disputed
Fetal risk on contactCan cause genital malformations in a male fetus if a pregnant partner is exposed.	Severe	Rare	Clinical

06 Legal status

United States

Prescription (compounded / approved formulation)

A dedicated topical formulation has regulatory approval; compounded versions also used · as of Jan 2026

Prescription medicine

as of Jan 2026

07 References

Efficacy and safety of a novel topical finasteride spray for androgenetic alopeciaJournal of the American Academy of Dermatology, 2023

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.