Trenbolone acetate ( USAN , BANM ) (brand names Revalor (in combination with estradiol ), Finaplix , Finajet ; former developmental code name RU-1697 ), also known as 19-nor-δ 9,11 -testosterone 17β-acetate or as 19-norandrost-4,9,11-trien-17β-ol-3-one 17β-acetate , is a synthetic , injected anabolic-androgenic steroid (AAS) and derivative of 19-nortestosterone (nandrolone) that is used in veterinary medicine .    It is the C17β acetate ester and a long-acting prodrug of trenbolone (19-nor-δ 9,11 -testosterone).   
Injectable steroids are injected into muscle tissue, not into the veins. They are slowly released from the muscles into the rest of the body, and may be detectable for months after last use. Injectable steroids can be oil-based or water-based. Injectable anabolic steroids which are oil-based have longer half-life than water-based steroids. Both steroid types have much longer half-lives than oral anabolic steroids. And this is proving to be a drawback for injectables as they have high probability of being detected in drug screening since their clearance times tend to be longer than orals. Athletes resolve this problem by using injectable testosterone early in the cycle then switch to orals when approaching the end of the cycle and drug testing is imminent.
Often referred to as Tren Ace or Tren-A has a half life of around 48 hours, due to its short half life Tren Ace needs to be injected a minimum of every second day. Most people choose to use Tren Ace in cutting cycles accompanied with other fast acting steroids such as Testosterone Propionate and Winstrol . Trenbolone acetate usually comes in 10ml vials dosed between 80 and 100mg/ml. Due to the many harsh side effects that come with using Trenbolone, many users choose to use the Acetate version so that they can discontinue use if needed and within a few days the side effects will start disappearing.