Trenbolone acetate, sold under brand names such as Finajet and Finaplix among others, is an androgen and anabolic steroid (AAS) medication which is used in veterinary medicine, specifically to increase the profitability of livestock by promoting muscle growth in cattle. It is given by injection into muscle.

Side effects of trenbolone acetate include symptoms of masculinization like acne, increased hair growth, voice changes, and increased sexual desire. The drug is a synthetic androgen and anabolic steroid and hence is an agonist of the androgen receptor (AR), the biological target of androgens like testosterone and dihydrotestosterone (DHT). It has strong anabolic effects and weak androgenic effects, as well as potent progestogenic effects, no estrogenic effects, weak glucocorticoid effects, and no risk of liver damage. Trenbolone acetate is an androgen ester and a long-lasting prodrug of trenbolone in the body.

Trenbolone acetate was discovered in 1963 and was introduced for veterinary use in the early 1970s. In addition to its veterinary use, trenbolone acetate is used to improve physique and performance, and is purchased from black market suppliers. The drug is a controlled substance in many countries and so non-veterinary use is generally illicit.