When you use any kind of steroid or testosterone over the course of three weeks or longer, your body stops making natural testosterone. Because of this, you need to make sure to implement PCT in order to help your body start producing natural testosterone again. You will need to start your therapy 10 days after your last dose of Sustanon 250, and all you need is a SERM, or Selective Estrogen Receptor Modulator. Nolvadex is generally regarded as one of the best, and you will use 40mg per day for the first two weeks, 20mg per day for the next two weeks, and then 10mg a day for one more week. You can continue it for a sixth week if necessary.
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.