Injectable anabolic steroids are dissolved in an oil or water-like liquid to which a small amount of benzyl alcohol and/or other substances may be added to maintain sterility. Some injectable anabolic steroids commonly used by athletes are testosterone enanthate, sustanon, trenbolone, nandrolone decanoate, and boldenone undecylenate. The period of action is 4-6 days (one shot per week is enough). This type is popular because it contains more active ingredient, has a long period of action and costs an order of magnitude less than the tablet form.