Finasteride
An oral prescription drug, approved at 1 mg for male pattern hair loss, that lowers production of the androgen DHT.
Finasteride Biological Classification
Investigated within physiological and chemical models.
What kind of compound
Small molecule
Small-molecule 5-alpha-reductase type II inhibitor, supplied as oral tablets.
Human testing on file
0human records
0 animal · 1 total indexed. Approved drug product in the United States.
Regulatory position
FDA-approved for male pattern hair loss in men only (1 mg); not approved for women.
Studied for
Approved oral androgen-pathway treatment
Reviewed 13 November 2026
Known safety concerns in this file
- The label carries warnings and precautions, including sexual adverse experiences and effects on prostate-specific antigen.
- Finasteride is not indicated for women; the label addresses pregnancy risk.
- This record is not a complete safety profile or a prescribing guide.
Commonly compared with
- Dutasteride — Dual 5-alpha-reductase inhibitor; not FDA-approved for hair.
- Minoxidil — Approved topical treatment with a different mechanism.
- Pyrilutamide — Investigational topical androgen-receptor blocker.
What is Finasteride?
An oral prescription drug, approved at 1 mg for male pattern hair loss, that lowers production of the androgen DHT. A small-molecule 5-alpha-reductase inhibitor approved at 1 mg for male pattern hair loss. A separate 5 mg product is approved for benign prostatic hyperplasia; the two are not interchangeable as hair-loss products.
Why are people interested in it?
Androgenetic alopecia in men is driven by follicular sensitivity to DHT; finasteride is the established pharmacological test of that mechanism.
Primary Research Categories
- Hair-growth drugs
- Small-molecule drugs
- Approved drug substances
How does it work in the body?
Inhibits type II 5-alpha-reductase, reducing conversion of testosterone to dihydrotestosterone. Lower scalp DHT slows follicular miniaturisation in responders.
Biological Pathway Overview
Finasteride Receptor & Target Interactions
This compound is evaluated in scientific research for its interactions with target cellular receptors and signaling cascades. Consult the evidence section below for specific peer-reviewed papers.
5-alpha-reductase type II
Named in the published mechanism discussion for this compound.
DHT synthesis
Named in the published mechanism discussion for this compound.
Androgen receptor signalling
Named in the published mechanism discussion for this compound.
Key Distinction: Approval applies to the specific indication and product on the label, not to every use of the molecule.
What has actually been demonstrated in humans?
Randomised trials in men with mild-to-moderate androgenetic alopecia support the approved indication. It is not approved for women.
Pharmaceutical Reality vs. Unregulated Research Chemicals
FDA-approved for male pattern hair loss in men only (1 mg); not approved for women. Reliable prediction of who will respond.
What is still uncertain or unknown?
Reliable prediction of who will respond. The natural history of reported persistent sexual adverse effects after stopping. Long-term outcomes beyond the trial periods.
Research at a Glance
Open the full evidence file (1 records)1 record in this file
- REGULATORY1
Publication span: 2022
What Has Actually Been Studied
- PROPECIA (finasteride) tablets — prescribing information (FDA approved labelling, 2022) — Approved product labelling.
What is Still Unknown
What we know
Editorial reading of the records below, labelled as Therapept analysis. How records are built
What remains uncertain
Preparation and Handling
Lyophilized peptides ship as freeze-dried powders; whatever happens next involves diluents, concentrations and storage conditions that are compound- and product-specific.
United States Regulatory Status
FDA-approved drug substance
Application: NDA 020788 (PROPECIA) — approved 19 December 1997
Approved Indication: PROPECIA (finasteride 1 mg) is indicated for male pattern hair loss (androgenetic alopecia) in men only. The label states that efficacy in bitemporal recession has not been established and that the product is not indicated for women.
- PROPECIA, NDA 020788, approved 19 December 1997 for androgenetic alopecia in men.
- The approved label limits the indication to men, and states that efficacy in bitemporal recession has not been established.
- Finasteride 5 mg (PROSCAR) is a different approved product, indicated for benign prostatic hyperplasia.
- The label carries warnings and precautions, including effects on prostate-specific antigen interpretation and reports of sexual adverse experiences. Regulatory status is not a safety assessment.
Technical Chemical SpecificationsClick to view CAS, sequence, and molecular formulas
- Molecular weight
- 372.55 g/mol
- Sequence length
- Not recorded
- CAS number
- 98319-26-7
- PubChem CID
- 57363
- Compound class
- Small-molecule 5-alpha-reductase type II inhibitor, supplied as oral tablets
- Sequence
- Unknown / Unassigned
- Molecular formula
- C23H36N2O2
- Molecular weight
- 372.55 g/mol
- CAS number
- 98319-26-7
- PubChem CID
- 57363
Sources
Last reviewed 13 November 2026 · Compiled by Therapept Editorial · How these records are built