Last updated: March 2026
Stanozolol (Winstrol) has the unusual distinction of being FDA-approved — for hereditary angioedema and aplastic anemia — while remaining one of the most recognized cutting AAS. Available in oral and injectable forms, non-aromatizing, and notorious for joint dryness. This reference covers its pharmacology, documented effects, hepatotoxicity, and harm reduction context.
Stanozolol is a heterocyclic AAS — it has a pyrazole ring fused to the A-ring of the steroid nucleus, making it unique in structure among AAS. This pyrazole modification prevents aromatization and confers unusually high anabolic:androgenic selectivity.
The fused pyrazole ring at C-3/4 of the A-ring completely prevents aromatase-mediated conversion to estradiol. This gives stanozolol a unique pharmacological profile among AAS: high anabolic potency with no estrogenic activity. Users experience dry, hard gains — no water retention, no gynecomastia risk from the compound itself.
Stanozolol inhibits hyaluronic acid synthesis in synovial tissue, reducing the viscosity and quantity of synovial (joint) fluid. This produces the characteristic "drying out" of joints that bodybuilders describe — reduced cushioning, often leading to joint pain, crackling, and increased injury risk during heavy lifting. This effect is typically reversible upon discontinuation.
Stanozolol's FDA-approved indication — hereditary angioedema — is mediated through increased hepatic synthesis of C1-inhibitor protein. Patients with HAE have deficient C1-inhibitor, causing recurrent swelling attacks. Stanozolol (Winstrol, Winzomol) raises C1-inhibitor levels by 50–100%, dramatically reducing attack frequency. This clinical use demonstrates real therapeutic value independent of anabolic effects.
Oral stanozolol is 17α-alkylated and hepatotoxic. Injectable stanozolol (an aqueous suspension) bypasses first-pass metabolism and is significantly less hepatotoxic per milligram — though injectable Winstrol is notorious for painful injections due to its water-based, crystalline particle suspension. Both forms cause similar anabolic and androgenic effects; the liver safety difference is the primary distinction.
Data from FDA-approved clinical trials (HAE, aplastic anemia) and pharmacological studies on stanozolol.
Winstrol's combination of hepatotoxicity (oral), joint dryness, and severe lipid effects requires multi-system monitoring.
Dosing schedules, interaction warnings, and cycle protocols for 50+ compounds — all in one place.
This page is for educational and harm reduction purposes only. It is not medical advice. Stanozolol (Winstrol) is a Schedule III controlled substance in the United States. While it holds FDA approval for hereditary angioedema at therapeutic doses, non-medical use is illegal. It is banned by WADA and all major sports organizations. Use at bodybuilding doses carries significant health risks including hepatotoxicity, cardiovascular disease (severe HDL suppression), joint injury, and HPTA suppression. MeetPeptide does not endorse or encourage the use of controlled substances. Consult a qualified physician before any decisions regarding hormone use.