Testosterone is a sex hormone primarily responsible for male sexual characteristics. Although testosterone is present in women in much lower levels than in men, it does play a role in women, as well. In men, abnormally low testosterone levels can develop due to a condition known as hypogonadism. Additionally, testosterone levels gradually decrease with increasing age in men. Several different hormone replacement supplements are available. However, doctors usually only recommend these supplements for men with hypogonadism, not for otherwise healthy, aging men, according to Harvard Health Publications.
Gels
Testosterone transdermal gels are the most popular supplements currently used, reports an article in Reviews in Urology. These gels are sold under the brand names AndroGel and Testim. The gels are typically applied once per day to the abdomen, shoulders and upper arms, causing the testosterone to be absorbed through the skin. Gels tend to cause less skin irritation and result in more constant levels of testosterone than other available formulations.
Skin Patches
Several different types of testosterone patches that can be applied to the skin are also available. The Androderm patch is usually applied somewhere on the upper body, such as the back, abdomen or upper arm. This patch also achieves fairly reliable testosterone levels; however, many patients have reported the side effect of skin irritation, according to a 2004 article in "Reviews in Urology." Patches applied directly to the scrotum have also been tried in the past; however, they often caused highly variable levels of testosterone in the blood.
Injections
Testosterone injections used to be widely used for testosterone replacement therapy. The common formulations need to be injected into a large muscle, such as the thigh or buttocks, every one to two weeks. Studies have shown that these injection also cause variable levels of testosterone. Immediately after the injection, testosterone levels are often too high, leading to a sense of euphoria. During the time leading up to the next injection, testosterone levels can fall below normal, and symptoms of hypogonadism often return, "Reviews in Urology" explains.
Buccal Cavity
Another more recently developed testosterone supplement is Striant, which delivers testosterone in a putty-like material. Striant is placed in the buccal cavity, the small groove just above the front teeth, where the gums join the inside of the upper lip. Once activated by saliva, Striant releases testosterone, which is absorbed into the bloodstream, explains GeorgiaHealthInfo.gov.
Oral Formulations
Oral testosterone supplements are very rare. Studies have found that oral administration of testosterone results in poor, highly variable levels of testosterone in the blood, according to GeorgiaHealthInfo.gov. An oral testosterone supplement called Andriol is produced by a company in The Netherlands, but it is not commercially available in the United States.
