This research report indicates that there appears to be no harm to mouse models when given additional testosterone. As Ed indicated in his email to me, however, this testing was done on mice and not on humans.
Testosterone Treatment Fails to Accelerate Disease in Mouse ModelsDoctors Erica S. Chevalier-Larsen and Diane E. Merry reported in Disease Models & Mechanisms:
Transgenic AR112Q and non-transgenic mice were implanted with timed-release pellets designed to deliver 4-6 ng/ml of testosterone for 90 days. Over the course of the experiment, implantation of testosterone pellets increased circulating testosterone an average of threefold, from 0.40±0.23 ng/ml; this is a significant elevation of testosterone levels in treated animals over those implanted with placebo pellets. Although 90-day testosterone pellets were used, we observed a decline in potency of the pellets by the end of the 90-day period (months three and six).
Implantation of new pellets at the end of 90 days restored circulating testosterone levels. Although circulating testosterone was elevated in treated mice, motor function assays did not reveal any effect of testosterone treatment on phenotype. Motor function assays were performed monthly for 6 months; results were consistent for all 6 months of treatment. Beginning at 3 months of age (1 month following treatment), AR112Q males showed decreased rotarod performance, regardless of T-treatment, when compared with non-transgenic T-treated males.
The entire report can be read by following this link to download the paper: Research Report (PDF)