Like any other anabolic steroid, using a supplement like Anavar will suppress natural production of testosterone. Be aware that Anavar is one of the mildest supplements for reducing testosterone production. Exogenous testosterone as a part of your supplement plan can help keep your natural testosterone production on track. If you do not do this, then you can have low testosterone , resulting in things like fatigue, lethargy, decreased muscle mass, and more. Some of this will require you figuring out what works for you. Since each and every physiology is so different, there may be a trial period where you work out any testosterone issues with your doctor. Be aware that once all artificial testosterone put into your body by you is gone, natural testosterone levels will resume as normal. Also be aware that you can damage the natural production of testosterone in your body by overdosing on anabolic steroids. It is often suggested that you should include a SERM and HCG with a PCT for best results.
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.