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.
One study appeared to show that gw 50156 side effects included the growth of cancer cells but on further inspection, the results could be considered misleading. The study of gw1516 which was carried out on mice included 1000 times the recommended dose, taken over a prolonged period of time. As no individual would be taking such an inflated level of gw501516, there is debatable value attached to this particular study. Nevertheless, despite the criticism of this study, it was sufficient for GSK to drop the project so shouldn’t be dismissed completely.