look at AST, MRM, and Mass Quantities
check out this article:
Journal of Enteral and Parenteral Nutrition. 23 (1) : suppl S16, abstr #62, 1999.
It seems that no matter where you look today, someone has come out with a new testosterone pre-cursor or prohormone. Androstenedione, 4-androstenediol, 5-androstenediol, 19-nor androstenedione, 19-nor androstenediol, 7-keto DHEA. We even made one up and "circulated" it in hushed undertones near prying ears. Sure enough within three weeks we had inquiries from several companies asking how they could obtain it. The beauty of each of these prohormones is that there is virtually no data to support their cleverly marketed contentions. That is, until now! At the conclusion of one of our ongoing clinical trials on prohormone research we found that androstenedione had a marginally better effect over 4-androstenediol when it came to converting into testosterone. In a randomized, double blind, placebo controlled, cross over clinical trial at the University of Texas at Arlington we found both of these prohormones to raise testosterone by 16% (4-androstenediol) and 26% (androstenedione). However, this does not answer the critical question of whether or not it actually increases muscle mass or, for that matter, is subject to side effects.