Updated September 2026. 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 designer steroids 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. It is also, in the United Kingdom, subject to a legal framework quite different from the one that applies to SARMs.
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 an active steroid, 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 seized and marketed products and mapped its human metabolites for detection purposes. This establishes identity, structure and metabolic fate. It says nothing about benefit.
Case reports of harm. The largest body of clinical writing that concerns Epistane itself, discussed below.
Doses used in the research
There are no research doses to report for methylepitiostanol, because there are no efficacy trials. Products on the supplement market historically declared amounts in the range of 10 to 40 mg daily, but those figures come from marketing rather than from any study, and several of the published liver injury cases involved products used at label amounts or below. SARMs Store does not supply Epistane for human consumption and gives no dosing guidance.
Side effects reported
The hepatology literature is where Epistane appears most often. Multiple case reports describe cholestatic liver injury in young men following use of 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 designer steroids: 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-steroidal, non-alkylated, and have human trial data showing modest lean mass gains with reversible hormonal changes and no liver enzyme elevation at trial doses. Epistane is a methylated steroid with no efficacy data and a documented hepatotoxicity signal. Compared with other methylated designer steroids 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.
Legal status in the UK, 2026
This is where Epistane differs sharply from the SARMs sold alongside it.
SARMs are not controlled under the Misuse of Drugs Act 1971. Anabolic steroids are. They sit in Class C, Part 1 of Schedule 4, and the legislation covers not only named compounds but esters, ethers and a wide definition capturing steroidal structures with anabolic effect. Methylepitiostanol is a 17-alpha-alkylated androstane derivative, and the prevailing view is that compounds of this structural class fall within those provisions. Under Schedule 4 Part 1, possession for personal use is not an offence, while supply, offering to supply, production and importation with intent to supply are.
Because classification questions of this kind can turn on specific structural analysis, this page does not state a categorical conclusion about any individual product. Anyone supplying, importing or holding methylepitiostanol in the UK should take their own legal advice and check the current Home Office and MHRA positions. If sold or advertised for human use it would separately be an unlicensed medicine. SARMs Store sells it strictly for laboratory research.
For athletes the position is unambiguous. Methylepitiostanol is an exogenous anabolic androgenic steroid prohibited at all times under section S1.1a of the WADA Prohibited List, and it is detectable by accredited laboratories.
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. Dexterz 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 a controlled drug in the UK? Anabolic steroids are Class C under the Misuse of Drugs Act 1971 and methylepitiostanol is generally treated as falling within that class. Take legal advice rather than relying on a summary.
Is Epistane detectable in a drugs test? Yes. Its human metabolites have been characterised for anti-doping purposes and it is prohibited at all times by WADA.
Related reading
- SARMs versus steroids and prohormones
- M-Sten (methylstenbolone): the research record
- Do the studies support a PCT after SARMs?
- Are SARMs legal in the UK? 2026 update
Research product: Dexterz Labs Epistane 10 mg, 90 capsules
Sources: Nasr J, Ahmad J, Dig Dis Sci 2009;54:1144-1146. Shah NL et al., Clin Gastroenterol Hepatol 2008;6:255-258. Japanese clinical literature on epitiostanol and mepitiostane in breast cancer, 1970s onwards. Anti-doping metabolite characterisation literature on methylepitiostanol. Misuse of Drugs Act 1971, Schedule 4 Part 1. WADA Prohibited List 2026.