Testosterone Undecanoate is a modified form of testosterone, where a undecanoic acid ester has been attached. Esterified forms of testosterone are less polar than free testosterone, and are absorbed more slowly from the area of injection. Once in the bloodstream, the ester is removed to yield free, active testosterone. Esterified forms of testosterone are designed to prolong the window of effect following administration, allowing for a less frequent injection schedule compared to injections of free, unesterified steroids. Nebido is designed to maintain physiological levels of testosterone for up to 14 weeks after injection. The half life of Testosterone Cypionate & Testosterone Enanthate is approximately 8 days after injection, requiring a more frequent injection schedule and less stable blood hormone levels than Nebido potentially offers.

As far as being a prescribed medication like Testosterone Cypionate and Enanthate, Nebido has yet to be cleared by the FDA, although it is already currently being prescribed in 86 foreign countries.

Muscular Development Magazine writer William Llewellyn published an article in the March 2010 issue on Nebido and its current FDA bid for acceptance. Click on the links below to read the article.

Page 1

Page 2

References

Llewellyn, William. Anabolics. 9th ed. Jupiter, FL: Molecular Nutrition, 2009.

Llewellyn, William. “U.S. Aveed/Nebido Delayed.” Muscular Development Magazine Mar. 2010: 299-300. Print.