Testosterone undecanoate or testosterone undecylate is an ester of testosterone which is used for the treatment of male hypogonadism, and is currently under research for use as a male contraceptive. Testosterone undecanoate is sold and distributed under the brand names Andriol, understor, nebido, pantestone, restandol. Andriol is a version of the anabolic steroid testosterone undecanoate developed by the pharmaceutical company organon. Testosterone is said to enter the body as a fat through the lymphatic system, experience from user indicates that in dose of less than 240mg per day. Effects are negligible, except at every onset of use, while even in higher dose; Effects are still minimal.
Testosterone undecanoate is therefore thought that most of the steroid is somehow not making it into the blood stream. Testosterone undecanoate is a long-acting man-made version of testosterone, the natural male sexual hormone. Testosterone is responsible for the normal growth and development of male sex organs and characteristics. It includes growth and development of male organs of penis, testicles, prostate, body hair, vocal cord thickening, and muscle and fat distribution.
Testosterone undecanoate is a synthetic androgen ester which acts as a prodrug of testosterone, and hence is considered to be a natural and bioidentical form of testosterone. Unlike other testosterone esters, testosterone undecanoate is available in both oral and intramuscular formulations.
As an intramuscular injection, it is much longer-acting than most other testosterone esters. Along with testosterone cypionate, testosterone enanthate, and testosterone propionate, testosterone undecanoate is one of the most widely used testosterone esters.