Mesterolone, marketed under brand names like Proviron, is a synthetic androgen and anabolic steroid (AAS) that is orally active. It is derived from dihydrotestosterone (DHT) and has a chemical structure that makes it resistant to metabolic breakdown, allowing it to maintain its activity when taken orally. Unlike many other anabolic steroids, Mesterolone is not considered to be significantly anabolic for muscle building in the same way as testosterone or nandrolone derivatives. Its primary clinical uses have historically centered on androgen deficiency or male infertility, though its role in these areas has significantly diminished with newer treatment options.
In the context of performance and physique enhancement, Mesterolone is sometimes used for its anti-estrogenic properties and its ability to increase circulating free testosterone levels. It is generally not used as a primary muscle-building agent due to its relatively weak anabolic effects compared to other AAS. However, its androgenic nature means it can still contribute to virilization and other androgen-related effects.
Mesterolone is a controlled substance in many regions, including the United States, due to its potential for misuse and abuse. Its use should always be under the guidance and prescription of a qualified healthcare professional.
Deep dive
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Known interactions
Category rule: peptide × hormone
Note
Injectable peptides plus hormones can have overlapping or compounding effects that aren't always well characterized.
Track bloodwork with a provider; don't assume combinations are neutral.
Frequently asked
Sources referenced
["DrugBank (Mesterolone)", "PubChem (Mesterolone)", "European Medicines Agency (EMA) - Summary of Product Characteristics (SmPC) for Proviron (Mesterolone)", "National Institute on Drug Abuse (NIDA) - Anabolic Steroid Abuse", "Cochrane Library (general reviews on male infertility treatments)"]
Stackwise compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician.
Related compounds
Others in the hormone category or studied for the same goals.