Boldenone Undecylenate 200 is an injectable anabolic-androgenic steroid (AAS) supplied in 10 mL vials at 200 mg/mL, dissolved in oil with preservatives. Primarily for veterinary use in horses to enhance muscle growth, appetite, and recovery, it is not approved for human use in most countries. Administered intramuscularly, it has a long half-life of ~14 days. Possible side effects include androgenic (acne, hair loss), estrogenic (water retention, gynecomastia), cardiovascular risks, and suppression of natural testosterone. It is contraindicated in pregnancy, liver/kidney disease, and hormone-sensitive cancers, and should be stored at 15–30°C, protected from light.