The full, current guide is our Epistane research guide.
Epistane is sold by SARMs Store strictly as a research compound. Nothing on this page is medical advice or an instruction for human use.
Epistane occupies an unusual position among the compounds sold as research material. Unlike most compounds in this category it has a legitimate pharmaceutical ancestor with a real clinical history, so part of its mechanism is genuinely documented. What it does not have is any efficacy trial of its own, and what it does have is a body of published case reports describing liver injury.
What Epistane is
Epistane is the market name for methylepitiostanol, chemically 2-alpha,3-alpha-epithio-17-alpha-methyl-5-alpha-androstan-17-beta-ol. Each part of that structure explains something.
The 2,3-epithio group is a sulphur-containing three-membered ring fused across the A ring. It is inherited directly from epitiostanol, a compound developed in Japan and marketed there as Thiodrol for the treatment of breast cancer. Epitiostanol is an anti-oestrogen, used clinically for its ability to reduce oestrogenic activity, with a mechanism generally understood to involve suppression of gonadotrophin release and interference with oestrogen signalling rather than classical aromatase inhibition. Mepitiostane, an ether derivative developed to improve oral activity, was also marketed in Japan.
The 17-alpha-methyl group is the modification added to make the molecule survive first-pass metabolism when taken orally. It is also the modification associated across the whole class of oral androgens with hepatotoxicity, and it is the single most clinically important feature of the compound.
Methylepitiostanol is therefore an orally active, 17-alpha-alkylated androgen derived from a real anti-oestrogenic pharmaceutical. It appeared on the supplement market in the late 2000s, sold as a prohormone, although strictly it is not one: it is active as itself, not a precursor.
What the research found
There is no published clinical trial of methylepitiostanol for muscle gain, strength or body composition. Nothing in the peer-reviewed literature establishes an effect size, and no page can honestly quote one.
What does exist falls into three groups.
The parent compound literature. Epitiostanol and mepitiostane were studied in Japan as breast cancer treatments from the 1970s onwards, with clinical reports on anti-oestrogenic efficacy. Those studies describe the parent molecules in a cancer population, not the methylated derivative sold as Epistane and not healthy trained people.
Analytical and metabolism work. Methylepitiostanol has been characterised in the anti-doping literature, where laboratories have identified it in marketed products, found a retail Epistane that also contained a different isomer and a second steroid, and shown that the standard steroid screen picks it up (Okano and colleagues, 2009). This establishes identity and detection. It says nothing about benefit.
Case reports of harm. The largest body of clinical writing that concerns Epistane itself, discussed below.
Side effects reported
The hepatology literature is where Epistane appears most often. Published reports, including a series of four people described by Petrov and colleagues in Archives of Toxicology in 2020, describe long-lasting cholestatic liver injury after products labelled as Epistane, typically with jaundice, severe pruritus, markedly raised bilirubin and a cholestatic enzyme pattern, sometimes with recovery taking weeks to months. This picture is characteristic of 17-alpha-alkylated androgens as a class and is well established for closely related compounds: Nasr and Ahmad, in Digestive Diseases and Sciences in 2009, described severe cholestasis and renal failure associated with methasterone, and Shah and colleagues in Clinical Gastroenterology and Hepatology in 2008 reported methasterone-associated cholestatic liver injury in a series of patients.
Beyond the liver, the effects expected from any androgen apply: suppression of endogenous testosterone and luteinising hormone, adverse changes to the lipid profile with HDL cholesterol typically falling substantially, and in some reports raised blood pressure. Because the compound is anti-oestrogenic rather than aromatising, oestrogen-related effects are less prominent, which is the basis of most of its marketing. That trade-off does not reduce the hepatic or lipid risk.
Comparison with related compounds
Compared with SARMs, Epistane is a different class entirely. Ostarine and LGD-4033 are non-alkylated, and have human trial data showing modest lean mass gains with reversible hormonal changes and no liver enzyme elevation in the trials. Epistane is a methylated compound with no efficacy data and a documented hepatotoxicity signal. Compared with other methylated compounds such as methasterone or methylstenbolone, it sits in the same structural family and carries the same class risk; its distinguishing feature is the epithio group and the anti-oestrogenic character it confers.
How to check a supplier
For a compound in this class the certificate of analysis is not a nicety. Ask for the batch-specific document from an independent laboratory, with identity confirmed by HPLC or LC-MS, a stated purity figure, and a batch number matching the bottle. Check the label declares the chemical name as well as the market name, states the amount per capsule and the capsule count, and carries a research-only notice. Alpha Labs Epistane is made in the UK at 10 mg per capsule, 90 capsules per bottle, and batch certificates of analysis are being published on the product page as testing is completed.
Frequently asked questions
Is Epistane a prohormone? Not strictly. A prohormone is a precursor that converts to an active hormone. Methylepitiostanol is already an active androgen.
Where does Epistane come from? It is a 17-alpha-methylated derivative of epitiostanol, a compound marketed in Japan as Thiodrol for breast cancer treatment.
Why is Epistane described as anti-oestrogenic? The 2,3-epithio structure it inherits from epitiostanol confers anti-oestrogenic activity, which is why the parent compound was used in breast cancer.
Is Epistane hard on the liver? It is 17-alpha-alkylated, the structural feature associated with cholestatic liver injury across this class, and case reports describing exactly that pattern following Epistane use are published in the hepatology literature.
Is Epistane detectable in a drugs test? Yes. Anti-doping laboratories have shown it is picked up by the standard steroid screen, and it is prohibited at all times by WADA.
Related reading
- SARMs versus prohormones
- M-Sten (methylstenbolone): the research record
- Do the studies support a PCT after SARMs?
- Browse the range: prohormones range
Research product: Alpha Labs Epistane 10 mg, 90 capsules
Sources
Primary papers and official guidance cited in this guide, linked so each one can be checked directly.
- Petrov PD et al., Arch Toxicol 2020;94:589-607 (cholestasis after Epistane in four people, and its mechanism in human liver cells). PubMed 31894354
- Okano M et al., Drug Test Anal 2009;1:518-525 (analysis of retail Epistane and related products). PubMed 20355167
- Matsuzawa A, Yamamoto T, Cancer Res 1976;36:1598-1606 (epitiostanol as an anti-oestrogen in a mouse mammary tumour model). PubMed 178425
- Nasr J, Ahmad J, Dig Dis Sci 2009;54:1144-1146 (severe cholestasis and renal failure with methasterone, sold as Superdrol). PubMed 18720005
- Shah NL et al., Clin Gastroenterol Hepatol 2008;6:255-258 (methasterone-associated cholestatic liver injury, 5 cases). PubMed 18187367
- WADA Prohibited List 2026.