Boldenone undecylenate is an esterified form of boldenone, a synthetic anabolic-androgenic steroid structurally related to testosterone. The undecylenate ester contributes to a prolonged release profile following intramuscular administration.

EQ 300 identifies a stated 300mg strength. Boldenone undecylenate has historically been associated primarily with veterinary medicine rather than routine human treatment. Exposure may affect endogenous hormone production, fertility, hematocrit, lipid metabolism, and cardiovascular health.