Metenolone
Metenolone is a synthetic anabolic steroid that has been licensed in some countries, including Japan, for conditions such as aplastic anaemia, osteoporosis and severe wasting. It is not an approved medicine in the UK or US.
Reference information, not medical advice. Enhanced Training Studio doesn't sell, supply or recommend any substance. Doses are left out on purpose: only a prescriber can set one. How this library is written.
What it is
Metenolone (also spelled methenolone) is a synthetic anabolic–androgenic steroid. It has been made as an injection, metenolone enanthate (Primobolan Depot), and as tablets, metenolone acetate (Primobolan) [1, 2, 3]. It has been used medically for aplastic anaemia and some other conditions [2, 3]. It is not an approved medicine in the UK or US. It is a Schedule III controlled substance in the US and a Class C drug in the UK [4, 5].
How it works
Metenolone acts on the androgen receptor, like testosterone. Chemically it is a modified form of dihydrotestosterone (DHT) with an added methyl group at position 1 and an extra double bond [4]. The enanthate form is an injected ester and the acetate form is taken by mouth [1, 3].
Approved medical uses
None in the UK or US.
- Ireland (EU): a licence for Primobolan Depot, containing metenolone enanthate, was issued in 1979 and withdrawn in 1989 [1].
- Japan: Japan's medicines regulator lists a prescription-only metenolone acetate tablet (Primobolan, Bayer), with a label revised in 2020. Its listed uses are osteoporosis, severe wasting from chronic kidney disease, cancer, injury or burns, and bone marrow failure from aplastic anaemia [3].
The US National Library of Medicine also records metenolone enanthate as used for aplastic anaemia [2].
What the research shows
- Limited and older evidence. Human evidence comes mainly from older clinical use in conditions such as aplastic anaemia and wasting [2, 3].
- Label warnings from clinical use. The Japanese product label warns of liver dysfunction and jaundice, and reports liver tumours in people with aplastic anaemia given anabolic steroids at high doses over long periods [3].
- Effects on hormones. The label notes suppression of testicular function in men with prolonged high-dose use, and masculinising effects in women [3].
- Non-medical use. Most current human information on metenolone outside medical care comes from people using several steroids together at supraphysiological doses. These studies are observational, and harms are hard to link to one drug [7].
Known risks and side effects
- Liver: liver dysfunction and jaundice; liver tumours with long-term high-dose anabolic steroid treatment [3, 6].
- Effects in women: deepening of the voice and other masculinising changes, which may be hard to reverse once they develop [3, 8].
- Effects in men: suppressed testicular function, reduced sperm count, infertility and breast development [3, 8].
- Not for use in androgen-dependent cancers or in pregnancy [3].
- Heart and blood vessels: heart attack, stroke, high blood pressure and deep vein thrombosis with steroid misuse [8]; cardiovascular disease and increased risk of death with non-medical use [7].
- Mental health: aggression, mood swings and paranoia; dependence, with depression and anxiety on stopping [8].
- Sport: metenolone is prohibited at all times under the World Anti-Doping Agency (WADA) Prohibited List [9].
Blood tests commonly monitored
There are no UK, US or EU monitoring guidelines for metenolone, because it is not approved there. The Japanese product label advises regular checks during treatment, especially long-term use, because of the risk of liver dysfunction [3]. Liver injury from anabolic steroids can show up as raised liver enzymes or cholestasis (a build-up of bile) [6].
For testosterone, the closest approved medicine in this class in the UK and US, the Endocrine Society guideline recommends monitoring [10]:
- Testosterone level during treatment [10].
- Haematocrit (the proportion of red blood cells), with treatment withheld if it rises above 54% [10].
- PSA (prostate-specific antigen) in men, with urology referral for a confirmed rise [10].
Anyone who has used metenolone should talk to a doctor about appropriate tests.
If you and your doctor are monitoring treatment, Enhanced Training Studio keeps a private log on your phone: what you take and when, your blood test results over time, and how you feel. How tracking works.
Sources
- Health Products Regulatory Authority. Primobolan Depot Amps (metenolone enantate): withdrawn medicine details. HPRA, accessed 2026. HPRA
- US National Library of Medicine. Methenolone enanthate. MeSH Supplementary Concept Record C028758, accessed 2026. MeSH
- Pharmaceuticals and Medical Devices Agency (Japan). Primobolan tablets (metenolone acetate) prescribing information. PMDA, 2020. PMDA
- US Code of Federal Regulations. 21 CFR 1308.13, Schedule III. Legal Information Institute, Cornell Law School, accessed 2026. LII
- Home Office. List of most commonly encountered drugs currently controlled under the misuse of drugs legislation. GOV.UK, 2025. GOV.UK
- National Institute of Diabetes and Digestive and Kidney Diseases. Androgenic Steroids. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, NCBI Bookshelf, 2020. LiverTox
- Pope HG Jr, Wood RI, Rogol A, Nyberg F, Bowers L, Bhasin S. Adverse health consequences of performance-enhancing drugs: an Endocrine Society scientific statement. Endocrine Reviews, 2014. Endocrine Society
- NHS. Anabolic steroid misuse. NHS website, 2026. NHS
- World Anti-Doping Agency. World Anti-Doping Code International Standard: Prohibited List 2026. WADA, 2025. WADA
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. Journal of Clinical Endocrinology and Metabolism, 2018. Endocrine Society
Related
Last reviewed 7 October 2026. General information, not medical advice. Found a mistake? Email [email protected].