Boldenone Undecylenate — Veterinary Vademecum Drug Reference

Dosage & Administration Guidelines

Species	Route	Dose	Frequency	Duration & Clinical Notes
Dog	IM	1-5 mg/kg	Weekly	Duration: Up to 6 weeks Notes: Use with caution; monitor for signs of androgen excess.
Cat	IM	1-2 mg/kg	Weekly	Duration: Up to 4 weeks Notes: Limited data; use only if potential benefit outweighs risks.
Horse	IM	0.5-1.1 mg/kg	Every 3 weeks	Duration: As needed Notes: Not approved for performance enhancement; withdrawal times must be observed.
Cattle	IM	0.5-1.0 mg/kg	Every 3 weeks	Duration: As needed Notes: Not approved in many countries; extra-label use requires veterinary oversight.
Small Ruminants	IM	0.5-1.0 mg/kg	Every 3 weeks	Duration: As needed Notes: Extra-label use; not commonly recommended.

Clinical Indications & Species Uses

General Indications

Anabolic support in chronic debilitating conditions
Promote weight gain and muscle mass
Stimulate erythropoiesis in anemia

Dog (Canine)

Supportive therapy for chronic wasting diseases
Anemia
Muscle wasting
Convalescence after surgery or illness

Horse (Equine)

Improve appetite and weight gain in debilitated horses
Support recovery from illness or surgery
Anemia
Muscle development in performance horses (though not approved for this)

Cattle (Bovine)

Improve weight gain and feed efficiency in beef cattle (though not approved in many countries)
Supportive therapy in debilitated animals

Pharmacology & Mechanism of Action

Drug Class: Anabolic Steroid | Pharmacological Group: Androgen / Anabolic Steroid

Mechanism of Action: Boldenone undecylenate is a synthetic anabolic-androgenic steroid (AAS) derived from testosterone. It exerts its effects by binding to androgen receptors (AR) in target tissues, leading to increased protein synthesis, nitrogen retention, and muscle growth. The undecylenate ester prolongs the duration of action by slowing release from the injection site. Boldenone also stimulates erythropoietin release, increasing red blood cell production, and has a relatively lower androgenic potency compared to testosterone, making it favored for lean muscle gain.

Pharmacodynamics: Boldenone promotes positive nitrogen balance, enhances protein synthesis, and increases appetite. It has anabolic:androgenic ratio of approximately 100:50 (compared to testosterone 100:100). It increases muscle mass, strength, and red blood cell count. It may also improve bone density and overall condition. In animals, it is used to reverse catabolic states, improve weight gain, and support recovery from illness or injury.

⚡ Pharmacokinetics Summary

Absorption: After intramuscular injection, boldenone undecylenate is slowly absorbed from the injection site due to the long-chain ester. Peak plasma concentrations occur within days to weeks depending on the formulation and species.

Distribution: Boldenone is widely distributed in the body, with high affinity for androgen receptors in muscle, bone, and reproductive tissues. It is also bound to plasma proteins, primarily sex hormone-binding globulin (SHBG) and albumin.

Metabolism: Boldenone is metabolized in the liver via reduction and conjugation. The undecylenate ester is hydrolyzed to release boldenone, which is then further metabolized to various metabolites, including 5α-dihydroboldenone and other reduced products.

Excretion: Metabolites are excreted primarily in urine, with some in bile. The elimination half-life is prolonged due to the slow release from the depot injection.

Half-Life: Horses: approximately 5-7 days; Dogs: approximately 3-5 days; Cattle: approximately 4-6 days (based on limited data).

Bioavailability: High (nearly 100%) when administered intramuscularly due to slow release; oral bioavailability is negligible due to first-pass metabolism.

Protein Binding: Approximately 90-95% bound to plasma proteins (SHBG and albumin).

Available Formulations & Strengths

Injectable Solution 50 mg/mL, 100 mg/mL, 200 mg/mL (IM)

Contraindications & Clinical Warnings

Contraindications:

Pregnancy (may cause virilization of female fetus)
Lactation (may pass into milk)
Known hypersensitivity to boldenone or other anabolic steroids
Prostatic carcinoma or other androgen-dependent neoplasia
Hypercalcemia (may worsen)
Cardiac, renal, or hepatic disease (may exacerbate fluid retention)

Warnings & Clinical Precautions:

Use with caution in animals with pre-existing cardiac, renal, or hepatic disease.
May cause sodium and water retention, leading to edema.
May suppress endogenous testosterone production; monitor reproductive function.
In food animals, observe withdrawal times; extra-label use is regulated.
In horses, use is prohibited in competition; check regulatory rules.
Do not use in pregnant or lactating animals unless absolutely necessary.
Use sterile technique for injection; may cause injection site reactions.

Adverse Effects & Reactions

Common:

Injection site pain or swelling
Increased aggression or behavioral changes
Increased libido
Mild fluid retention

Serious / Severe:

Hepatotoxicity (with prolonged use)
Cardiac hypertrophy
Suppression of endogenous testosterone
Virilization in females
Premature closure of epiphyseal growth plates in young animals

Rare:

Allergic reactions
Blood dyscrasias
Hypercalcemia
Cholestatic jaundice

Key Drug Interactions

Interacting Drug / Class	Clinical Effect & Mechanism	Severity
Corticosteroids	Increased risk of fluid retention and edema; may enhance catabolic effects.	Moderate
Anticoagulants (e.g., warfarin)	May enhance anticoagulant effect; monitor coagulation parameters.	Moderate
Insulin or oral hypoglycemics	May alter glucose metabolism; monitor blood glucose levels.	Mild
Hepatotoxic drugs (e.g., NSAIDs, azoles)	Increased risk of hepatotoxicity.	Moderate

Overdose & Toxicity Management

Signs of Toxicity:

Severe fluid retention
Edema
Hepatotoxicity
Aggression
Hypercalcemia
Cardiac abnormalities

Emergency Treatment Protocol: Treatment is symptomatic and supportive. Discontinue the drug. Manage fluid retention with diuretics if necessary. Monitor liver function and cardiac status. In severe cases, consider supportive care including intravenous fluids and electrolyte management. There is no specific antidote.

Food Animal Withdrawal Times

🥩 Meat: 30 days🥛 Milk: 7 days

Withdrawal times are not established for boldenone undecylenate in many countries; extra-label use requires extended withdrawal periods. Consult regulatory guidelines. In cattle, a withdrawal time of at least 30 days for meat and 7 days for milk is recommended, but this may vary.

Storage, Handling & Regulatory Information

Storage Temperature: Store at controlled room temperature 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C.

Light Sensitivity: Light-sensitive — protect from direct exposure.

Handling & Special Conditions: Protect from light. Keep container tightly closed. Do not freeze.

Dispensing Status: Prescription Required (Rx Only)

Approval Status: Not approved by the FDA for veterinary use in the US. Available as a compounded product or for research use.

Extra-Label (Off-Label) Use: In the US, extra-label use of boldenone undecylenate in food animals is prohibited by the FDA because it is not approved for use in food animals and is considered a potential public health risk. In horses, it is a controlled substance in some racing jurisdictions. Use in performance animals is prohibited. In the EU, it is not authorized for use in food-producing animals.

Clinical Pearls & Practice Notes

💡 Clinical Insights: Boldenone undecylenate is a long-acting anabolic steroid used in veterinary medicine primarily for its anabolic effects in debilitated animals. It is not approved for veterinary use in many countries, and its use is often extra-label. It is important to weigh the benefits against potential adverse effects, especially in animals with underlying conditions. In food animals, its use is strictly regulated due to potential residues. In performance animals, it is prohibited. Clinical monitoring should include liver function, electrolyte balance, and behavioral changes. Due to the lack of extensive safety data, it should be used with caution and only when alternative therapies are not available.

References & Literature

📚 Plumb's Veterinary Drug Handbook
📚 Papich Veterinary Pharmacology and Therapeutics
📚 Compendium of Veterinary Products (CVP)