Conflicting data in the medical literature about the benefits and risks of testosterone therapy is confusing for medical professionals and patients. It is important to carefully review studies to determine the form of testosterone used. Natural testosterone must not be confused with synthetic derivatives or "anabolic steroids," which, when used by athletes and bodybuilders, have caused disastrous effects.
For example, administration of synthetic non-aromatizable androgens, like stanozolol or methyltestosterone, causes profound decreases in HDL-C ("good cholesterol") and significant increases in LDL-C ("bad cholesterol"). Yet, hormone replacement with aromatizable androgens, such as testosterone, results in lower total and LDL cholesterol levels, while having little to no impact on HDL cholesterol levels.