This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The purpose of this study is to determine how two new oral formulations (medications to be taken by mouth) of male hormone Testosterone (also called T-esters) are metabolized by human body. This will be done by giving different doses of these T-esters to hypogonadal men (men deficient in male hormone) and measuring how much of these medications remains in the blood at set time points. These new formulations contain male hormone testosterone in the form of Testosterone Enanthate (TE) or Testosterone Undecanoate (TU) combined with a lipid (fatty) compound. The lipid part of these medications makes absorption of the testosterone portion easier and more efficient by being largely absorbed in the intestine instead of first going to and being broken down by the liver. TE has been used as an injection for the treatment of hypogonadal men for over 50 years and is the standard of care in the United States. There is no oral preparation of TE available. Oral TU and recently TU injections have been approved in Europe, Asia, and Australia for male hormone treatment of hypogonadal men. The TI preparation under study is formulated differently from the TU marketed in other countries. It is anticipated that this new TU preparation may last longer. These esters, when injected or taken by mouth, are broken down to testosterone portion and the ester portion. The ester portion is metabolized without any action in the body (i.e. cause no side effects).