Stanozolol
17alpha-Methyl-5alpha-androstano[3,2-c]pyrazol-17beta-ol (Androstanazole)
Also known as: Winstrol-V · Menabol · Neurabol · Stanol · Strombaject · Androstanazole · Estanozolol · Methylstanazole · NSC-43193 · Stanozololum · Win-14833
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an anabolic agent per labeled indications (Small Breeds) | 1-2 mg PO twice daily; or 25 mg deep IM, may repeat weekly. | PO/IM | q12h (PO) or weekly (IM) | Several weeks, depending on response | 🌎 NA |
| As an anabolic agent per labeled indications (Large Breeds) | 2-4 mg PO twice daily; or 50 mg deep IM, may repeat weekly. | PO/IM | q12h (PO) or weekly (IM) | Several weeks, depending on response | 🌎 NA |
| For anemia secondary to chronic renal failure | 1-4 mg PO once daily | PO | q24h | — | 🌎 NA |
| For anemias secondary to uremia | 2-10 mg PO twice daily | PO | q12h | — | 🌎 NA |
| As an anabolic/appetite stimulant | 1-4 mg PO twice daily OR 1-2 mg PO twice daily or 25-50 mg IM weekly | PO/IM | q12h (PO) or weekly (IM) | — | 🌎 NA |
| For canine cognitive dysfunction | 2 mg/kg IM for 4-6 weeks with 1-2 mg (total dose) PO once daily for dogs less than 23 kg and 4 mg (total dose) PO once daily for dogs greater than 23 kg. | IM/PO | q24h (PO) | 4-6 weeks initially | 🌎 NA |
- For canine cognitive dysfunction: If drug has some positive effect, maintain oral dosing and gradually reduce injections to every 3-4 weeks.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an anabolic agent per labeled indications | 1-2 mg PO twice daily; or 25 mg deep IM, may repeat weekly. | PO/IM | q12h (PO) or weekly (IM) | Several weeks, depending on response | 🌎 NA |
- As an anabolic agent per labeled indications: EXTREME CAUTION: High incidence of hepatotoxicity in cats.
Small Mammals
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an appetite stimulant (Rabbits) | 0.5-2 mg PO once | PO | Once | Single dose | 🌎 NA |
Ferrets
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| General therapeutics | 0.5 mg/kg PO or SC twice daily | PO/SC | q12h | — | 🌎 NA |
- General therapeutics: Use with caution in hepatic disease.
Birds
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an anabolic agent to promote weight gain and recovery from disease | 0.5-1 mL/kg (25-50 mg/kg) IM once or twice weekly. | IM | Once or twice weekly | — | 🌎 NA |
- As an anabolic agent to promote weight gain and recovery from disease: Use with caution in birds with renal disease.
Reptiles
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Post-surgically and in very debilitated animals | 5 mg/kg IM once a week as needed | IM | weekly | As needed | 🌎 NA |
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| As an anabolic agent per labeled indications | 0.55 mg/kg (25 mg per 100 pounds of body weight) IM deeply. May repeat weekly for up to and including 4 weeks. | IM | weekly | Up to 4 weeks | 🌎 NA |
- As an anabolic agent per labeled indications: ARCI UCGFS Class 4 Drug. Contraindicated in breeding stallions and food animals.
Sheep
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For acute or subacute aflatoxicosis in ruminants | Stanozolol 2 mg/kg IM (plus activated charcoal 6.7 mg/kg as a 30% w/v slurry in M/15, pH 7 phosphate buffer). | IM | Single dose | — | 🌎 NA |
- For acute or subacute aflatoxicosis in ruminants: Do not combine with oxytetracycline therapy.
Goats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For acute or subacute aflatoxicosis in ruminants | Stanozolol 2 mg/kg IM (plus activated charcoal 6.7 mg/kg as a 30% w/v slurry in M/15, pH 7 phosphate buffer). | IM | Single dose | — | 🌎 NA |
- For acute or subacute aflatoxicosis in ruminants: Do not combine with oxytetracycline therapy.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Stanozolol is a synthetic anabolic-androgenic steroid (AAS) derived from testosterone. Historically, it was widely used in veterinary medicine to improve appetite, promote weight gain, increase strength and vitality, and treat anemia associated with chronic disease.
While FDA-approved commercial products (such as Winstrol®-V) are no longer marketed in the USA, the drug remains available through veterinary compounding pharmacies.
Clinical Pearl: Stanozolol has a notoriously high incidence of hepatotoxicity in cats. Its use in feline patients is highly discouraged unless absolutely necessary, and requires extreme caution and rigorous monitoring.
Though it possesses a higher anabolic-to-androgenic ratio compared to endogenous testosterone, androgenic side effects (such as behavioral changes and reproductive suppression) can still occur, particularly with prolonged use or high doses. It is a controlled substance due to its potential for human abuse.
Mechanism of action
Stanozolol is highly lipophilic and diffuses across the cell membrane to bind with intracellular androgen receptors.
- Anabolic Pathway: The receptor-hormone complex translocates to the nucleus → binds to specific DNA sequences (hormone response elements) → modulates transcription of target genes → increases protein synthesis (anabolism), promotes a positive nitrogen balance, and induces muscle hypertrophy.
- Erythropoietic Pathway: Stimulates the production of erythropoietin in the kidneys → stimulates bone marrow → increases red blood cell production (useful in treating anemia of chronic disease).
- Fibrinolytic Pathway: Enhances fibrinolysis after parenteral injection, which provides a theoretical basis for its use in treating feline aortic thromboembolism or thrombosis in nephrotic syndrome.
Safety & warnings
Contraindications
- Pregnant animals (Category X - teratogenic)
- Breeding stallions
- Food-producing animals
- Patients with hepatic dysfunction
- Patients with hypercalcemia
- Patients with a history of myocardial infarction
- Patients with pituitary insufficiency
- Patients with prostate carcinoma or benign prostatic hypertrophy
- Patients with mammary carcinoma
- During the nephrotic stage of nephritis
Adverse effects
- Hepatotoxicity (especially high incidence in cats)
- Sodium, calcium, potassium, water, chloride, and phosphate retention
- Behavioral changes (androgenic effects such as increased aggression)
- Reproductive abnormalities (oligospermia, estrus suppression)
- Mild androgenic effects (usually only at high doses or prolonged use)
Precautions
Extreme Caution: Use in cats due to a very high incidence of hepatotoxicity.
Caution: Use cautiously in patients with cardiac and renal dysfunction; enhanced fluid and electrolyte monitoring is required due to the potential for sodium and water retention.
Pregnancy Warning: FDA Category X / Papich Class D. Teratogenicity clearly outweighs any possible benefit. Contraindicated in pregnant animals. Use with extreme caution in nursing patients as it is unknown if it is excreted in maternal milk.
Drug interactions
Anabolic agents may potentiate the effects of anticoagulants; monitoring of INR/PT and dosage adjustment of the anticoagulant are recommended.
Anabolics may enhance the edema that can be associated with ACTH or adrenal steroid therapy.
Anabolics may decrease blood glucose and decrease insulin requirements; diabetic patients receiving insulin may need dosage adjustments.
Monitoring
- Androgenic side effects (behavioral changes)
- Fluid and electrolyte status (especially in cardiac/renal patients)
- Liver function tests (crucial in cats)
- RBC count and indices (if treating anemia)
- Weight and appetite
Pharmacokinetics
Elimination
No specific information located. Injectable suspension is generally dosed on a weekly basis.
Overdose
No specific information was located for this agent in veterinary species. In humans, sodium and water retention can occur after overdosage of anabolic steroids.
Treatment: Treat supportively and monitor liver function should an inadvertent overdose be administered.
Available products
Formulations
- Tablets
- Injectable suspension
Veterinary
- None commercially available. Previously available as Winstrol®-V tablets and injection. Currently available via compounding pharmacies.
Human-labeled
- None commercially available.
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Stanozolol tablets should be stored in tight, light-resistant packaging, preferably at room temperature.
Client information
Stanozolol is an anabolic steroid used to help pets gain weight, build muscle, or treat certain types of anemia.
- Administration: Tablets may be crushed and administered with food to make dosing easier.
- Safety Warning: This medication can cause severe liver damage, especially in cats. Your veterinarian will likely recommend regular blood tests to monitor liver function.
- Storage & Handling: Because of the potential for human abuse, stanozolol is a controlled substance. It must be kept in a secure area, strictly out of the reach of children and unauthorized individuals.
- Side Effects: Watch for signs of fluid retention (swelling), changes in behavior (such as increased aggression), or yellowing of the eyes/gums (jaundice), and report them to your veterinarian immediately.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.