Combined preparations . A number of trials have been carried out with implants containing two hormones. The combination of an oestrogen with an anabolic steroid, or with progesterone, has met with the greatest responses. Synovex-S has consistently increased gain as well as FCE, with responses averaging about 20% and 17% respectively (20, 21, 22, 34, 35, 36, 37, 42, 43, 44, 45, 46, 47, 48). Hexoestrol + TBA (usually 30 or 45 mg hexoestrol + 300 mg TBA) has resulted in marked increases in gain (24, 25, 26, 29, 49, 50, 51, 52, 53), of the order of 30% and in FCE (25, 49, 50, 51, 53) of the order of 20%. Oestradiol-17β + TBA (20/140 mg) has given similar results (27, 28, 37, 54, 55), as has Zeranol + TBA (36/300 mg), also recently tested (27, 37, 38, 39, 40, 41, 56).
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.