Testosterone
Testosterone cypionate, Testosterone enanthate, Testosterone propionate
Also known as: Depo-Testosterone · Delatestyl · AndroGel · Testopel · Synovex · Testosterone cyclopentylpropionate · Testosterone cypionate · Testosterone enanthate · Testosterone propionate · NSC-9166
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 |
|---|---|---|---|---|---|
| Testosterone-responsive urinary incontinence (may be used with phenylpropanolamine) in males | Testosterone propionate: approximately 2 mg/kg IM or SC 3 times per week. Testosterone cypionate: 200 mg IM once per month | IM/SC | 3 times per week / once per month | — | 🌎 NA |
| Testosterone-responsive urinary incontinence | Testosterone propionate: 2.2 mg/kg IM q2-3 days. Testosterone cypionate: 2.2 mg/kg IM once per month | IM | q2-3 days / once per month | — | 🌎 NA |
| Testosterone-responsive urinary incontinence | Testosterone cypionate: 2.2 mg/kg IM q4-8 weeks | IM | q4-8 weeks | — | 🌎 NA |
| Testosterone-responsive urinary incontinence | Testosterone propionate: 2.2 mg/kg IM or SC every 2-3 days. Testosterone cypionate: 2.2 mg/kg every 30 days or 200 mg IM every 30 days. | IM/SC | every 2-3 days / every 30 days | — | 🌎 NA |
| Estrus control | Testosterone enanthate or cypionate 0.5 mg/kg IM once every 5 days or methyltestosterone tablets 25 mg PO twice a week; this dose is for Greyhound-sized dogs. | IM/PO | once every 5 days / twice a week | — | 🌎 NA |
| To reduce mammary gland enlargement seen in pseudopregnancy | Testosterone enanthate or cypionate 0.5-1 mg/kg IM once | IM | once | — | 🌎 NA |
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Infertility or reduced libido | 0.1-1 mg every other day or every third day for 3-5 injections IM or SC. Not indicated for testis descent. | IM/SC | every other day or every third day | 3-5 injections | 🌎 NA |
| Testosterone-responsive urinary incontinence (may be used with phenylpropanolamine) in males | Testosterone propionate 5-10 mg IM as needed. | IM | as needed | — | 🌎 NA |
- Infertility or reduced libido: Using either testosterone cypionate or propionate
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| To produce an estrus-detector (teaser) animal (cull cows, heifers, steers) | Testosterone propionate 200 mg IM on day 1 and on days 4-9. On day 10, give 1 gram IM and attach a chinball marker and put with the breeding herd. To maintain the teaser give 1 gram booster every 10-14 days. | IM | varies | — | 🌎 NA |
| To produce an estrus-detector (teaser) animal (cull cows, heifers, steers) | Alternatively, initially give testosterone enanthate 0.5 gram IM and 1.5 gram SC (divided in two separate locations). After 4 days attach chinball marker and put in with breeding herd. To maintain, give 0.5-0.75 gram SC every 10-14 days. | IM/SC | varies | — | 🌎 NA |
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Testosterone is the principal endogenous androgenic steroid. In veterinary medicine, the use of injectable testosterone esters is primarily limited to specific hormonal and reproductive applications.
- Small Animals: Primarily used for the treatment of testosterone-responsive urinary incontinence in neutered male dogs and cats. It has also been used rarely to treat specific bilateral alopecia (dermatitis) in neutered male dogs.
- Large Animals: Used in bovine medicine to produce an estrus-detector (teaser) animal from cull cows, heifers, or steers.
- Clinical Note: Its efficacy for increasing libido or treating infertility/hypogonadism in domestic animals has generally been disappointing.
- Regulatory: Testosterone products are controlled substances (C-III) due to their anabolic steroid classification.
Mechanism of action
Testosterone is highly lipophilic and diffuses across target cell membranes. In many tissues, it is converted by 5-alpha-reductase → dihydrotestosterone (DHT). Both testosterone and DHT bind to intracellular androgen receptors → the receptor complex translocates to the nucleus → binds to DNA hormone response elements → modulates gene transcription.
- Urethral Tone: Helps maintain normal urethral muscle tone and mucosal integrity in neutered males.
- Anabolic Effects: Increases protein anabolism and decreases catabolism → retention of nitrogen, sodium, potassium, and phosphorus.
- Erythropoiesis: Stimulates erythropoietic stimulating factor (erythropoietin) → increases red blood cell production.
- Endocrine Feedback: Large exogenous doses exert negative feedback on the pituitary gland → inhibits luteinizing hormone (LH) and follicle-stimulating hormone (FSH) → inhibits spermatogenesis.
Safety & warnings
Contraindications
- Known hypersensitivity to the drug
- Prostate carcinoma
- Pregnancy (FDA Category X / Papich Class D)
Adverse effects
- Perianal adenomas
- Perineal hernias
- Prostatic disorders (enlargement)
- Behavior changes (aggression)
- Polycythemia (at high doses)
- Oligospermia or infertility (in intact males with chronic use)
Precautions
Use with caution in patients with renal, cardiac, or hepatic dysfunction. Teratogenic Warning: Contraindicated in pregnancy; causes congenital malformations and embryotoxicity. It is unknown if androgens are excreted in milk; consider milk replacers for nursing patients. Testosterone is a C-III controlled substance.
Drug interactions
May enhance the edema associated with ACTH or adrenal steroid therapy
Testosterone may decrease serum glucose levels
Testosterone cypionate may increase propranolol clearance
Testosterone may increase anticoagulant effects
Monitoring
- Clinical efficacy (resolution of incontinence, estrus detection behavior)
- Adverse effects (prostatic enlargement, aggression, perineal hernias)
- Hematocrit/PCV (for polycythemia with chronic use)
Pharmacokinetics
Absorption
Orally administered testosterone is rapidly metabolized by the GI mucosa and liver (first-pass effect). Esterified compounds (enanthate, cypionate) are less polar and more slowly absorbed from lipid tissue after IM injection, providing a duration of 2-4 weeks. Propionate has a shorter duration of action.
Distribution
Highly bound to a specific testosterone-estradiol globulin (98% in humans). The free form concentration determines the plasma half-life.
Metabolism
Metabolized in the liver.
Elimination
Excreted primarily in the urine (≈90%) and feces (≈6%).
Overdose
No specific acute toxicity information is available.
- Chronic Overdose: High dosages or chronic usage may result in oligospermia or infertility in intact males due to negative feedback on LH/FSH.
- Other Effects: Polycythemia (excessive red blood cells) has been reported in humans receiving high dosages.
- Treatment: Discontinue therapy and provide supportive care. Monitor hematocrit and prostatic size.
Available products
Formulations
- Injection (oil)
- Subcutaneous implant pellets
- Transdermal gel/patch
- Buccal system
Veterinary
- Component E-H (Testosterone propionate 200 mg / Estradiol benzoate 20 mg implant)
- Synovex-H (Testosterone propionate 200 mg / Estradiol benzoate 20 mg implant)
- Synovex-Plus (Testosterone propionate 200 mg / Estradiol benzoate 28 mg implant)
Human-labeled
- Depo-Testosterone Injection (100 mg/mL, 200 mg/mL)
- Delatestyl Injection (200 mg/mL)
- Testopel Implant Pellets (75 mg)
- Androderm Transdermal System
- AndroGel 1%
- Testim Gel 1%
- Striant Buccal System
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature; avoid freezing or exposing to temperatures greater than 40°C. If exposed to low temperatures, a precipitate may form but should redissolve with shaking and rewarming. Using a wet needle/syringe may cause cloudy solutions but will not affect potency.
Client information
🐾 What is Testosterone used for?
Testosterone is a male hormone used primarily in veterinary medicine to treat urinary incontinence in neutered male dogs and cats. It helps restore the muscle tone of the urethra to prevent urine leakage.
💊 How is it given?
It is typically administered as an injection (into the muscle or under the skin) by your veterinarian. The effects of a single injection can last for several weeks depending on the specific formulation used.
⚠️ Important Safety Warnings
PREGNANCY WARNING: Testosterone can cause severe birth defects. Pregnant women or women who may become pregnant MUST NOT handle this medication or come into contact with the injection site or bodily fluids of recently treated animals.
🔍 What to Monitor
Contact your veterinarian if you notice any of the following:
- Behavioral changes: Increased aggression, mounting, or restlessness.
- Straining to urinate or defecate: This could indicate an enlarged prostate.
- Lumps near the tail base: May indicate perianal tumors or hernias.
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.