Type 2 diabetes is a frustrating and sometimes debilitating condition that both scientists and doctors are struggling to keep up with. But a recent study in mice from the University of Edinburgh may provide clues about what causes diabetes in some patients. Scientists there discovered that men with low levels of testosterone could have an increased risk of type 2 diabetes.

Testosterone 101

Testosterone is a hormone present in both men and women, but at much higher levels in men. It is associated with typical male characteristics, such as face and body hair and muscles.

As men age, or when they're affected by certain health conditions, their ability to produce testosterone declines, resulting in lower testosterone levels in the blood and cells. Some contributing factors may include:

  • Certain medications
  • Chemotherapy
  • Injury
  • Illness
  • Loss of a testicle
  • Genetic conditions
  • Pituitary (an endocrine gland) dysfunction
  • Autoimmune disorders
  • Radiation exposure
  • Alcohol abuse
  • Stress

Over time, men with low testosterone levels may lose muscle mass and strength, and gain body fat; obesity may follow. Low testosterone levels in men are also associated with the following:

  • Erectile dysfunction
  • Low energy
  • Heart disease
  • High blood pressure
  • Depression

Linking Low Testosterone to Diabetes

While low testosterone levels can lead to obesity, a major cause of diabetes, the University of Edinburgh mice study found that low testosterone increases risk for diabetes even in subjects who were not overweight.

The study examined mice lacking androgen receptors, which are molecules that allow testosterone to act on fat cells and activate genes related to obesity and diabetes.

Without androgen receptors in their fat tissue, mice were testosterone-impaired; they became fatter than other mice, and developed insulin resistance when fed high-fat diets. (Like testosterone, insulin is a hormone; it allows the liver, muscles, and fat to absorb sugar and is responsible for regulating blood sugar levels. People with insulin resistance have a hard time using the insulin their bodies produce; they end up manufacturing more and more insulin to overcome the body's resistance to the hormone. Like obesity, the condition is a risk factor for type 2 diabetes.)

However, it wasn't just high fat diets and obesity that caused insulin resistance in the testosterone-impaired mice; these mice were more likely to develop insulin resistance regardless of body weight.

An Insulin Resistance Factor That's Not Related to Weight

Researchers think a protein called RBP4 plays a key role in regulating insulin resistance when testosterone is impaired; they found higher levels of the protein in such mice. Now, researchers are studying new treatments that regulate RBP4 production, which might reduce risk of diabetes in some men.

Treating Low Testosterone

Luckily, low testosterone levels in men can be treated. Testosterone injections, patches, gels, creams, implants, or pills can help replace the hormone. While testosterone therapy may not prevent men from developing diabetes, it might help them manage some of the conditions associated with low testosterone levels. If you suspect you have low testosterone, speak to your physician about your options.

Amber L. Taylor, MD, reviewed this article.



University of Edinburgh. "Low Testosterone Levels Linked to Diabetes." Web. 14 May 2012. Page accessed 14 August 2013.

Gagnon, Louise. "Testosterone Has Benefits for Metabolism, Weight Loss." Medscape Today News. Web. 18 July 2012. Page accessed 14 August 2013.

"Questions and Answers: Low Testosterone and Men's Health." Web. Hormone Health Network. Page accessed 14 August 2013.  

National Diabetes Information Clearinghouse. "Insulin Resistance and Prediabetes." U.S. Department of Health and Human Services. Web. Page last updated 22 Jan. 2013. Page accessed 14 August 2013.

Christina Wang, Graham Jackson, T. Hugh Jones, et al. "Low Testosterone Associated With Obesity and the Metabolic Syndrome Contributes to Sexual Dysfunction and Cardiovascular Disease Risk in Men With Type 2 Diabetes." Diabetes Care 2011; 34(7): 1669-1675. Page accessed 14 August 2013.