Methylstenbolone
Designer prohormone (2,3α-epithio-17α-methylstenbolone). Strong AR agonist with high hepatotoxicity.
WHAT IS METHYLSTENBOLONE?
Detailed overview
Methylstenbolone (M-Sten, Ultradrol, Methyl-D) is a **designer prohormone with chemical structure 2β,17β-dimethyl-2,3α-epithio-5α-androstane**. The 2,3α-epithio group replaces the aromatizable A-ring → no E2 conversion, hence a clean dry/hard muscle profile. In the US it was sold 2008-2012 as a dietary supplement under brand names like Iron Mag Labs Ultradrol, Antaeus Labs Methyl-D and others. FDA warning letters 2012-2013 targeted multiple manufacturers, then **DASCA 2014** classified it as Schedule III controlled. The **Robles-Diaz 2015 (Liver Int, PMID 25867306)** acute liver failure case-series analysis documented fulminant cholestatic hepatitis at 5-15 mg/day over 3-6 weeks in healthy young men, with several cases progressing to liver transplant. Hepatotoxicity high (17α-methylated oral), prostate side effects more pronounced than Superdrol.
Mechanism
AR agonist (anabolic 660 / androgenic 660)
Half-life
8-12 hours
Legal status
USA: DASCA 2014 controlled. EU: not uniformly regulated.
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 7
- Severe hepatotoxicity: as a 17-alpha-methylated oral steroid it caused documented acute cholestatic hepatitis and fulminant liver failure at 5-15 mg/day within 3-6 weeks (Robles-Diaz 2015), some cases progressing to liver transplant. Jaundice, pruritus, dark urine, elevated ALT/AST/bilirubin.
- Drastic lipid deterioration: oral 17-aa steroids typically crash HDL cholesterol and raise LDL, producing an unfavourable cardiovascular risk profile even within a short cycle.
- Marked androgenic effects: the symmetric 660:660 ratio means androgenic/prostatic activity is as strong as the anabolic effect, so acne, oily skin, androgenic hair loss (in predisposed users) and prostate hypertrophy occur.
- HPTA suppression: shutdown of endogenous testosterone production, testicular shrinkage, reduced libido and sperm count after the cycle, which without PCT (Clomid/Nolvadex) can cause prolonged hypogonadism.
- Raised blood pressure and cardiovascular strain: the steroid and lipid effects can cause hypertension and increased cardiovascular stress even during the short cycle.
- Mood and behavioural changes: increased aggression/irritability and sleep disturbance linked to the strong androgenic activity.
- Virilization in women: irreversible masculinising effects (voice deepening, hirsutism, clitoral enlargement) due to the strong androgenicity, unsuitable for women.
Contraindications · 7
- Any pre-existing liver disorder, elevated liver enzymes or prior drug-induced liver injury, an absolute contraindication given the documented fulminant hepatotoxicity.
- Pregnancy and breastfeeding: the strong androgenic effect severely harms the fetus (virilization), so it is strictly contraindicated in pregnancy.
- Women and adolescents: not to be used due to the marked, partly irreversible androgenic/virilizing effects and the risk of premature epiphyseal closure.
- Cardiovascular disease, hypertension or adverse lipid profile: the HDL crash and blood pressure rise worsen pre-existing cardiovascular risk.
- Prostate disease or prostate/breast carcinoma: the strong androgenic activity can stimulate androgen-sensitive tissues.
- Concurrent alcohol use, hepatotoxic drugs or NSAIDs: cumulative liver burden and increased toxicity risk.
- Competitive athletes: it is on the WADA prohibited list and its use leads to disqualification.
Related Performance Compounds
Same therapeutic category
Studies
Related research and clinical findings
Designer steroids - over-the-counter supplements and their androgenic component: review of an increasing problem
Rahnema CD, Crosnoe LE, Kim ED
Nutritional supplements cross-contaminated and faked with doping substances
Geyer H, Parr MK, Mareck U, Reinhart U, Schrader Y, Schänzer W.
Telegram
Have a question about Methylstenbolone?
Reach out to an advisor on Telegram. Performance compounds are presented with a harm-reduction approach, based on peer-reviewed evidence.
The information here is for educational and scientific purposes only. Performance-enhancing compounds (AAS, prohormones, stimulants, doping agents) are illegal without prescription in Hungary and most of the EU, and carry serious health and legal risks. WADA bans them in competitive sport. This is NOT a usage guide, and we do not encourage any illegal use. If you do use them, medical supervision and regular bloodwork are ESSENTIAL. Severe endocrine, cardiovascular, hepatic and psychiatric side effects are possible.