Finasteride

ID: finasteride

Aliases: Propecia, Proscar, 5-alpha-reductase inhibitor, 5ARI

Type: compound

Route/form: oral tablet in approved label context

Status: approved

Evidence level: approved / labelled

Best data tier: approved label + human controlled/review

Support scope: human

Source types: human_rct, label, meta_analysis

Linked sources: 4

Broad outcomes: Hair / alopecia, Hormones / fertility / sexual health, PEDs / AAS / thermogenics

Reading note: These are curation notes anchored to linked sources, not a clinical recommendation or protocol.

Targets / mechanism

• type II 5-alpha-reductase inhibition
• DHT suppression
• androgenetic alopecia treatment

Optimization domains

• hair
• androgenetic alopecia
• prostate
• DHT
• testosterone
• endocrine
• sexual health

Research basis

• Approved oral finasteride has human trial and label support for male androgenetic alopecia and BPH contexts.
• It is mechanistically relevant to androgen-stack hair-risk discussions because it blocks testosterone-to-DHT conversion in 5-alpha-reductase-sensitive tissues.

Limits, risks, and missing evidence

• It is not a universal hair-loss shield: it does not block direct androgen-receptor agonism from SARMs, testosterone itself, DHT-derived AAS, or non-5AR pathways.
• Sexual adverse effects, mood reports, semen/fertility context, PSA interpretation, pregnancy exposure risk, and post-finasteride-syndrome controversy need separated curation.

Risk flags

• prescription only
• sexual adverse effects
• mood reports
• fertility semen context
• psa interpretation
• does not block all androgens

Linked papers, labels, and reviews

1. DailyMed label: finasteride tablet
   label / dailymed_finasteride_label
   Finasteride label covering 5-alpha-reductase inhibition, DHT suppression, indications, warnings, and adverse reactions.
2. Finasteride in the treatment of men with androgenetic alopecia
   human_rct / pubmed_finasteride_aga_trials_1998
   Two one-year placebo-controlled trials plus extension data in men with male pattern hair loss.
3. Adverse sexual effects of treatment with finasteride or dutasteride for male androgenetic alopecia: a systematic review and meta-analysis
   meta_analysis / pubmed_finasteride_sexual_adverse_meta_2018
   Meta-analysis of sexual adverse effects in male androgenetic alopecia treatment with finasteride or dutasteride.
4. Effect of 1 mg/day finasteride on concentrations of serum prostate-specific antigen in men with androgenic alopecia
   human_rct / pubmed_finasteride_psa_rct_2007
   Randomized trial supporting PSA interpretation caveat even at 1 mg/day male-pattern-hair-loss dose.