When using a substantial amount of testosterone it is almost inevitable that at least some of it will be converted to estrogen via the aromatase enzyme. Now, aromatase is present mainly in belly fat, so the amount of testosterone converted to estrogen is largely dependent on how much extra fat one is carrying. The main side effects of a large conversion rate (testosterone -> estrogen) are extra water retention in the soft tissues and gynecomastia, the development of breast tissue. I meant bloating when I said 'ballooning'. Obviously, the two easiest ways to prevent this bloating are to lean out before testosterone administration and/or the use of an aromatase inhibitor, which occupies the enzyme and effectively prevents the circulating testosterone from being converted to estrogen. Many endocrinologists and urologists will shy away from prescribing AIs as an adjunct to testosterone administration due to the fact that it is an 'off label' use of the product. However, many anti aging clinics will prescribe AIs with testosterone for the first several months until the patient drops enough belly fat to have a low/healthy conversion rate of testosterone -> estrogen. The only thing about that is that most anti aging doctors are in it for the money, and therefore refuse to accept any kind of insurance, even if the insurance agreed to cover the treatment, AND the clinic will usually require you to sign up for their entire treatment plan, not just the AI (more $$$).
