Search Here

When men hit their middle-aged years, they start to experience a change in their bodies and mood. At the gym, they may start to lift lighter weights as their waistlines begin to expand. In the bedroom, their libido might not be as strong as they remember. All of these changes that men go through could be dubbed the male's menopause since their hormone levels are shifting dramatically as well. Testosterone has always been the doctors' explanation for these changes. However, according to a new study, a reduction in testosterone levels is not the only culprit. The researchers reported that lowered levels of estrogen, the female hormone, appear to be responsible for belly fat and reduced sexual desires.

"Some of the symptoms routinely attributed to testosterone deficiency are actually partially or almost exclusively caused by the decline in estrogens," said Dr. Joel Finkelstein, an endocrinologist at Harvard Medical School and the study's lead author according to the New York Times.

In one of the first studies to examine how estrogen affects men, the research team recruited 400 healthy young men between the ages of 20 and 50. The male participants were given drugs to stop the testosterone production in their bodies for 16 weeks. One group of randomly selected men was then placed on a placebo. Another group was given one of four doses of testosterone. One more group was giving estrogen-blocking drugs with testosterone supplements. All of the participants under went monthly blood tests and had their leg strength and body compositions measured. They were also given questionnaires about their physical and sexual activities.

The researchers first identified that a measurement of 550 nanograms of testosterone per deciliter of blood serum is healthy. Medical professionals state that levels fewer than 300 nanograms would need treatment. In this study, the researchers found that muscle strength and size were affected once testosterone levels fell under 200 nanograms. They found that when the levels reached 300 to 350, fat accumulation started. The researchers found that fat accumulation as also caused by reductions in estrogen. When it came to sexual desire, the researchers concluded that drops in both hormones reduced libido. However, until more research is done, the research team does not recommend men to start taking estrogen pills.

Finkelstein's team is planning on doing the study on older men. The study was published in the New England Journal of Medicine.