Trenbolone compounds have a binding affinity for the androgen receptor three times as high as that of testosterone. Once metabolised, the drugs have the effect of increasing nitrogen uptake by muscles, leading to an increase in the rate of protein synthesis. It also has the secondary effects of stimulating appetite, reducing the amount of fat being deposited in the body, and decreasing the rate of catabolism. Trenbolone has proven popular with anabolic steroid users as it is not metabolised by aromatase or 5?-reductase into estrogenic compounds such as estradiol, or into DHT. This means that it also does not cause any water retention normally associated with highly androgenic steroidal compounds like testosterone or methandrostenolone. It is also loved by many for the dramatic strength increases commonly experienced with it. Some short-term side effects include insomnia, high blood pressure, increased aggression and libido. However, since women will suffer virilization effects even at small doses, this drug should not be taken by a female. Urban wisdom/myth in bodybuilding culture, states that the use of the drug over extended periods of time can lead to kidney damage. The kidney toxicity has not yet been proven, and scientific evidence supporting the idea is suspiciously absent from the bodybuilding community that perpetuates this idea. The origin of this myth most likely has to do with the rust colored oxidized metabolites of trenbolone which are excreted in urine and often mistaken for blood. After Schanzer (Clin Chem 1996; 42(7): 1001-1020, Metabolism of anabolic androgenic steroids) trenbolone and 17epi-trenbolone are both excreted (in urine) as conjugates that can be hydrolyzed with beta-glucuronidase. This implies that trenbolone leaves the body as beta-glucuronides or sulfates, that means mostly non metabolized.
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.
To strengthen the anabolic properties of testosterone, more than 100 synthetic steroid derivatives have been described for human purposes. The anabolic effect promotes protein synthesis, muscle growth and erythropoiesis. In clinical practice, substances with anabolic effect are needed to overcome various catabolic states. However, none of these compounds are devoid of androgenicity. Androgenic and anabolic properties of anabolic steroids cannot be totally separated. Therefore, it is more appropriate to use the term anabolic androgenic steroids (AAS).