Educational reference only. Informational material drawn from peer-reviewed literature. Not medical advice and not a recommendation to use, dose, or modify any therapy. Decisions about hormone therapy should be made with a qualified healthcare provider.
Overview
Overview
Stanozolol is a synthetic anabolic-androgenic steroid (AAS), best known by the trade name Winstrol (Winstrol-V for veterinary use, also Stromba in some markets). It is one of the few AAS available in both oral and injectable forms, both of which are 17α-alkylated, an unusual feature among injectable AAS. Stanozolol was developed in 1962 by Winthrop Laboratories and remains FDA-approved for the treatment of hereditary angioedema (HAE), where it works by boosting C1-inhibitor protein levels to prevent life-threatening swelling attacks.
The compound's most public moment came in 1988 when Canadian sprinter Ben Johnson was stripped of his Olympic gold medal in the 100-meter sprint after testing positive for stanozolol, one of the most famous doping cases in sports history. This event significantly shaped public awareness of AAS use in athletics and accelerated WADA's anti-doping infrastructure development.
Forms
Available forms & half-lives
| Form | Approximate half-life |
|---|---|
| Oral tablet | ~9 hours |
| Injectable (aqueous suspension, "Winstrol Depot") | ~24 hours |
What it does
Main effects
- Strong anabolic activity with cosmetic muscle definition / "dry" appearance: basis of stanozolol's reputation in cutting cycles
- No aromatization to estrogen: pyrazole-ring A-ring modification prevents conversion; no water retention, no estrogen-mediated gynecomastia
- C1-esterase inhibitor stimulation: the basis of FDA approval for hereditary angioedema; stimulates hepatic production of C1-INH protein
- Pronounced SHBG reduction: substantially decreases SHBG, potentially increasing bioavailability of co-administered androgens
- Available in both oral and injectable forms: unusual flexibility for an AAS, though both forms carry the 17α-alkylation hepatic risk
What to watch for
Common side effects
- Severe hepatotoxicity in BOTH oral and injectable forms: both contain the 17α-methyl modification; injectable does NOT provide the hepatic safety advantage that injectable forms of other AAS provide; cholestasis, peliosis hepatis, and hepatic tumors documented
- Dramatic lipid changes: HDL reductions of 30–60% and LDL elevations of similar magnitude; among the most pronounced lipid effects of any AAS
- Cardiovascular adverse events: cardiomyopathy, MI, and sudden cardiac death documented in case reports; animal studies demonstrate direct cardiotoxic effects PMC: 12431587
- Joint pain and connective tissue effects ("Winstrol joints"): characteristic; reduced collagen synthesis and joint lubrication; often limits training or daily activity; may increase tendon injury risk
- Profound HPG axis suppression
- Severe acne and androgenic skin effects
- Scalp hair loss in genetically predisposed users: 5α-reductase inhibitors do not protect (stanozolol is already 5α-reduced)
- Severe virilization in women despite no aromatization: voice deepening and clitoral enlargement often irreversible
- Severe injection-site pain ("Winstrol PIP") with the aqueous suspension formulation: local swelling, abscess risk, crystallization
- Exceptionally long detection window for sport testing: injectable detectable for up to 9 weeks; oral up to 3 weeks
Key facts
Key facts worth knowing
- Stanozolol is 17α-alkylated in BOTH oral and injectable forms, making injectable Winstrol nearly as hepatotoxic as the oral form. This is unusual; most injectable AAS are not 17α-alkylated and therefore have minimal hepatic concerns. Injectable stanozolol does not provide the hepatic safety advantage that injectable forms of other AAS provide.
- Joint pain and connective tissue concerns are characteristic of stanozolol use. The compound is reported to reduce collagen synthesis and joint lubrication, sometimes producing severe joint pain that limits user willingness to continue. This effect is documented in clinical literature and is one of the compound's most consistently reported subjective features.
- The compound produces some of the most dramatic lipid profile changes of any AAS: pronounced HDL reduction and LDL elevation. This is part of why stanozolol has been associated with cardiovascular adverse effects in case reports.
- Cannot aromatize to estrogen due to its 5α-reduced structure. This produces the characteristic "dry" appearance and absence of water retention that makes stanozolol popular in cutting cycles.
- The injectable form is typically prepared as an aqueous suspension rather than oil-based, which produces characteristic injection-site pain ("Winstrol pip") and increases risk of injection-site complications.
- WADA detection: oral form detectable for approximately 3 weeks; injectable form detectable for up to 9 weeks, contributing to the Ben Johnson detection in 1988 and many subsequent doping positives.
Legal status
Legal status
Schedule III controlled substance in the United States (DEA). FDA-approved for hereditary angioedema treatment. WADA-prohibited at all times in competitive sport.