Finasteride

Finasteride is a synthetic 4-azasteroid and competitive inhibitor of 5α-reductase type II that blocks the conversion of testosterone into the more potent androgen dihydrotestosterone (DHT), and is used clinically in the management of both benign prostatic hyperplasia and androgenetic alopecia.

Enzymatic Mechanism of Action and DHT Reduction

5α-Reductase is a membrane-bound enzyme that exists in several isoforms. Finasteride specifically inhibits the type II isoform, which is predominantly expressed in prostatic tissue, hair follicles, and genital tissue. Through covalent binding to the enzyme–coenzyme complex, the conversion of testosterone to DHT is irreversibly blocked; serum DHT concentrations are reduced by approximately 65–70% at therapeutic doses, while testosterone levels rise modestly as a compensatory response. DHT has roughly five times greater affinity for the androgen receptor than testosterone, making its suppression biologically significant particularly in androgen-sensitive tissues such as the prostate and hair follicles. The clinical efficacy of finasteride is supported by numerous randomized controlled trials, which fundamentally distinguishes it from most compounds discussed in SARM/PCT research.

Pharmacological Profile and Clinical Contextualization in PCT Settings

In the context of hormonal research and PCT protocols, finasteride is used to modulate androgen-related side effects associated with elevated DHT levels — for example, with substance classes that tend to promote increased DHT conversion. Finasteride does not alter total testosterone production, but exclusively its peripheral conversion. The half-life in humans is approximately 5–6 hours, with an active metabolite phase of up to 24 hours. Adverse effects described in studies include changes in libido and ejaculatory parameters, which in the majority of cases were reversible upon discontinuation.

Range & Selection

The current range includes the following formulation:

Proscar | 5 mg/Tab | 50 tablets | Master Pharma – Oral tablet formulation containing 5 mg of finasteride per unit in a pack of 50 tablets; corresponds to the classic therapeutic dose strength used in clinical prostate studies.