When taken for more than 4-6 weeks, it can increase body mass and protein anabolism. However, for the body to build muscle one also has to eat a diet rich in calories. Most bodybuilders also take a combination of other hormones at the same time. Because testosterone is converted to estrogen in the fatty tissues, there is always the chance of developing gynecomastia and water retention. To prevent this, most bodybuilders add Arimidex or tamoxifen during the off cycle.
During testosterone injections, the natural body testosterone release is inhibited by feedback mechanism through inhibition of pituitary LH. At large doses, even spermatogenesis can be impaired. To allow for the hypothalamic-pituitary axis to recover, it is highly recommended that the drug be tapered off slowly over a period of a few weeks. Sudden discontinuation of the drug can lead to extreme fatigue, weight loss and susceptibility to fractures.
The manufacturers of certain testosterone products (., AndroGel and Striant) state that their products are contraindicated in patients with soybean, soy, or soya lecithin hypersensitivity because they are derived partially from soy plants. There is a risk of serious hypersensitivity reactions or anaphylaxis with the use of testosterone undecanoate (Aveed) oil for injection. These allergic reactions can occur after any injection of testosterone undecanoate during the course of therapy, including after the first dose. Observe patients in the healthcare setting for 30 minutes after an Aveed injection in order to provide appropriate medical treatment in the event of serious hypersensitivity reactions or anaphylaxis. The Aveed injection contains benzyl benzoate, the ester of benzyl alcohol and benzoic acid, and refined castor oil. Therefore, testosterone undecanoate use is contraindicated in patients with polyoxyethylated castor oil hypersensitivity, benzoic acid hypersensitivity, or benzyl alcohol hypersensitivity. Patients with suspected hypersensitivity reactions should not be re-treated with testosterone undecanoate injection.