Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis. The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. Due to its non-aromatizable nature and strong resistance to metabolism, trenbolone has a moderate to strong (negative) impact on lipid values and atherogenic risk. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.
I do not consider trenbolone to be capable of causing or aggravating gynecomastia. I do not know of a single case where the source of trenbolone was Parabolan (back when it was available), Finaplix H, or Component T-H. The problem appears to occur only when the source is an underground lab or the home preparation is made from powder from a black-market supplier. Since trenbolone’s wholesale price direct from a manufacturer is much higher than that of most anabolic steroids , it shouldn’t be surprising that substitution or partial substitutiion would often occur with underground products. Additionally, it might be that some have mistakenly made preparations from Finaplix S, which definitely would be capable of causing gyno, as that product includes estradiol benzoate as an ingredient.
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.