Finasteride (Proscar)
fin-AS-ter-ide
Category
Compound type
Phase / Status
FDA approved for BPH and male pattern baldness
Standard Dose
Daily
Half-life
Plasma elimination
Route(s)
Oral
Research Stage
Regulatory approval granted; post-market monitoring ongoing.
Overview
Finasteride is the go-to DHT blocker for guys who want to save their hair during a cycle without going nuclear on their entire hormonal system. It blocks only the type 2 5-alpha reductase enzyme, which drops DHT by about 70% -- enough to protect your hairline on moderate testosterone doses without the extreme side effects of its bigger brother dutasteride. The best part is reversibility: finasteride clears your system in days, so if you get side effects like low libido or brain fog, they tend to resolve quickly when you stop. It won't do much against really androgenic compounds like trenbolone or masteron though -- those are already 5-alpha reduced and bypass the enzyme finasteride blocks. Practical tip: 1mg daily is plenty for hair protection, and women who are or might become pregnant should not handle crushed or broken tablets at all.
Plain-language summary
Finasteride is the go-to DHT blocker for guys who want to save their hair during a cycle without going nuclear on their entire hormonal system. It blocks only the type 2 5-alpha reductase enzyme, which drops DHT by about 70% -- enough to protect your hairline on moderate testosterone doses without the extreme side effects of its bigger brother dutasteride. The best part is reversibility: finasteride clears your system in days, so if you get side effects like low libido or brain fog, they tend to resolve quickly when you stop. It won't do much against really androgenic compounds like trenbolone or masteron though -- those are already 5-alpha reduced and bypass the enzyme finasteride blocks. Practical tip: 1mg daily is plenty for hair protection, and women who are or might become pregnant should not handle crushed or broken tablets at all.
Administration Routes
- Oral
Also known as
Mechanisms
5-alpha reductase type 2 inhibitor
Detailed mechanism
Selective inhibitor of type 2 5-alpha reductase enzyme, preventing conversion of testosterone to dihydrotestosterone (DHT). Less complete DHT suppression than dutasteride but shorter duration of action.
Safety
Side effects
- Reduced libido
- Erectile dysfunction
- Gynecomastia
- Depression
- Anxiety
Reported benefits
- Reduces DHT by 70%
- Prevents hair loss
- Less systemic effects than dutasteride
- Reversible
Safety profile
Generally well-tolerated but can cause sexual side effects. Effects are reversible after discontinuation.
Clinical trials
Completed clinical trials leading to FDA approval for BPH and male pattern baldness.
Structure
Verified structure
Finasteride (Proscar)
Exact 2D structure can be rendered from a PubChem-backed canonical SMILES string.
- Chemical Formula
- C23H36N2O2
- Molecular Weight
- 372.54 g/mol
- CAS Number
- 98319-26-7
- InChIKey
- DBEPLOCGEIEOCV-UHFFFAOYSA-N
Stack Context
Stacks with
References
- 1View source
The effect of finasteride on the risk of acute urinary retention and the need for surgical treatment among men with benign prostatic hyperplasia (PLESS study, NEJM)
1998
- 2View source
Finasteride in the treatment of men with androgenetic alopecia (J Am Acad Dermatol)
1998
- 3View source
The influence of finasteride on the development of prostate cancer (Prostate Cancer Prevention Trial, NEJM)
2003
This profile summarizes research literature for education only. It is not medical advice, and it does not diagnose, treat, or recommend a dose. Consult a qualified professional before changing a protocol.