Stanozolol
Stanozolol is a synthetic anabolic steroid derived from testosterone. It was formerly sold as a prescription medicine in the US under the name Winstrol, but it is not a currently licensed human 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
Stanozolol is a synthetic anabolic–androgenic steroid made from testosterone. It has been produced as tablets taken by mouth and as an injectable form. In the US it was sold for human use under the brand name Winstrol [1]. It is a controlled drug: anabolic steroids are Schedule III substances in the US [6] and Class C drugs in the UK [4].
How it works
Like other androgens, stanozolol binds to androgen receptors inside cells. The receptor then moves to the nucleus and switches on genes involved in growth and development [1]. Stanozolol is a 17-alpha-alkylated steroid. This chemical change slows its breakdown in the liver, which allows it to work when taken by mouth, and changes the balance between its muscle-building and masculinising effects [1]. Steroids of this type can cause cholestatic liver injury [1].
Approved medical uses
None currently in the UK or US.
Stanozolol was previously marketed for human use in the US as Winstrol [1]. Approved uses for androgenic steroids as a group have included hereditary angioedema (an inherited condition causing attacks of swelling), androgen deficiency, delayed puberty and some breast cancers [1].
What the research shows
- Limited and old evidence. The human safety information on stanozolol summarised by LiverTox comes mainly from case reports published in the 1970s and 1980s [1].
- Liver injury. LiverTox estimates that acute cholestasis (reduced bile flow causing jaundice and itching) may occur in about 1% of patients treated with some 17-alpha-alkylated steroids, including stanozolol, and that the risk is likely related to dose [1].
- Case reports. Published reports describe older adults who developed severe jaundice and itching within months of starting stanozolol, including three patients aged 62 to 65. Another patient developed jaundice with liver biopsy changes suggesting a hypersensitivity reaction, which resolved slowly after stopping the drug [1].
- Long-term liver risks of the class. Long-term use of androgenic steroids has been linked to liver adenomas and, typically after 5 to 15 years of use, liver cancer [1].
Known risks and side effects
- Liver problems, including cholestatic jaundice, peliosis hepatis (blood-filled cysts in the liver that can rupture), liver adenomas and liver cancer [1].
- Heart and circulation. Anabolic steroid misuse is linked to high blood pressure, heart attack and stroke [4].
- Effects in men. Reduced sperm count, shrunken testicles and breast development [4].
- Effects in women. Excess facial and body hair, a deeper voice and smaller breasts [4].
- Mental health. Aggression, mood swings, paranoia and manic behaviour have been reported with misuse [4].
- Cholesterol changes. Anabolic steroid use can raise cholesterol levels [6].
- Growth in adolescents. Anabolic steroid use can permanently stunt growth in young people [6].
- Stanozolol is prohibited at all times in sport under the World Anti-Doping Agency (WADA) Prohibited List [5].
Talk to a doctor about any concerns.
Blood tests commonly monitored
There are no current official monitoring guidelines for stanozolol, because it is not a currently licensed human medicine in the UK or US. For the closest approved androgen medicines, testosterone injections, labels and guidelines advise monitoring:
- Liver function tests [2].
- Cholesterol (lipid profile) [2].
- Haemoglobin and haematocrit [2, 3].
- PSA (prostate-specific antigen) in men for whom prostate monitoring is appropriate [3].
Because stanozolol is a 17-alpha-alkylated steroid, liver injury is a particular concern with this type of steroid [1].
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
- National Library of Medicine. Androgenic Steroids. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury, NCBI Bookshelf, updated 2020. NCBI Bookshelf
- Pfizer. DEPO-Testosterone (testosterone cypionate) injection: US prescribing information, revised 2025. Pfizer labeling
- 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
- NHS. Anabolic steroid misuse. NHS
- World Anti-Doping Agency. The 2026 Prohibited List, International Standard, as published in the Treaty Series of the Kingdom of the Netherlands (Tractatenblad 2026, No. 25). Officielebekendmakingen.nl
- US Drug Enforcement Administration, Diversion Control Division. Anabolic Steroids: drug and chemical information, 2025. DEA
Related
Last reviewed 7 October 2026. General information, not medical advice. Found a mistake? Email [email protected].