Evidence of a key role for testosterone in the cause and treatment of obesity, the metabolic syndrome and diabetes

May 2012

The rapid increase in rates of obesity in both the developed and the developing world has serious consequences. Nearly all obese adults suffer from at least one obesity-related disease, such as type 2 diabetes, high blood pressure, cardiovascular disease, cancer, or joint disorders. A recent comprehensive review has looked beyond the place of testosterone in the male reproductive system and for the treatment of erectile dysfunction (impotence) to examine the key role of testosterone in the development and treatment of obesity and associated diseases. The article reviewed the evidence for the effects on insulin sensitivity, visceral fat and cholesterol levels of returning low testosterone levels to normal, and addressed the safety of testosterone, particularly in elderly men.

Key findings

Testosterone plays a key role in obesity, blood glucose control and the sensitivity of the body to insulin and the processing of fats such as cholesterol and triglycerides:

  • The different male and female sex hormones cause fat mostly to be stored around the breasts, hips and thighs in women before the menopause and around the abdominal organs (under the skin or as deeper, visceral fat) in adult males. However, as men get older, visceral fat increases to a greater extent in men who have low levels of testosterone. Visceral fat is unhealthy and is linked to insulin resistance, diabetes high blood pressure and heart disease.
  • There is a link between low testosterone in the blood and increased insulin resistance (the ability of the body to process sugars and fats)
  • Low testosterone levels increase the risk of type 2 diabetes mellitus and the metabolic syndrome (MetS) and are a warning sign of increased risk of developing and/or dying from cardiovascular disease
  • It is becoming apparent that decreasing testosterone levels in aging men is not simply related to age, but that other diseases contribute to low testosterone
  • Testosterone therapy reverses part of the unfavourable risk profile for the development of diabetes and narrowing of the arteries (atherosclerosis) in men with hypogonadism (low testosterone)
  • Although there is increasing evidence of a beneficial effect of testosterone therapy on visceral fat and other cardiovascular risk factors, it is important to establish a proper diagnosis of hypogonadism before initiating testosterone therapy.

Source: Saad F, Gooren LJ. The role of testosterone in the etiology and treatment of obesity, the metabolic syndrome, and diabetes mellitus type 2. J Obes 2011:pii:471584.

Background information

Although the role of testosterone therapy in treating erectile dysfunction and restoring libido in men with low testosterone is well accepted, the awareness that testosterone has an important role in the cause of obesity has not been as widespread. However, there is a growing acceptance that testosterone is an essential hormone for many aspects of health throughout the life of a man, and the administration of testosterone therapy to aging men with hypogonadism is a responsible approach provided accepted treatment guidelines are followed.