Dr. Joel Finkelstein at the Massachusetts General Hospital Endocrine Unit and colleagues published new research in the Sept. 12, 2013, issue of the New England Journal of Medicine that indicates estrogen levels are just as important a factor in age related loss of energy and sex drive in men as testosterone levels.
The researchers found that some of the age related symptoms that men experience are the exclusive province of estrogen levels and cannot be addressed by present testosterone replacement therapies. Men produce a small amount of estrogen throughout their sexually active life time through a specific chemical pathway that begins with testosterone.
Low testosterone levels are accompanied by low estrogen levels.
A comparative test of men between 20 and 50 years of age split 150 men into two groups. One group used testosterone replacement gel exclusively while the other group used an estrogen conversion inhibitor and testosterone gel.
Sexual function was found to necessitate both estrogen and testosterone. Estrogen was also found to regulate fat accumulation.
The researchers suggest that the forms of testosterone used for therapy should be capable of being converted into estrogen. At present, some testosterone therapies are not capable of this conversion. Considering the 500 percent increase in U. S. testosterone prescriptions in the last decade the scientists recommend testing for estrogen levels prior to and during testosterone therapy.