Look for studies and reviews of Shalender Bhasin (or just S. Bhasin - muscle mass, psychological, insulin sensitivity, atherosclerosis, etc. ) and a guy name Tenover (test as HRT for andropause). Just type in testosterone and the last name as the keywords.
For recent studies, use the science citation index, which is like a reverse medline of sorts: you put in a citation, e.g., one of Bhasin's studies and it lists the studies which have cited it. Kind of like the find more studies like this link you'll find at www.pubmed.com (nih site to medline.)