Testosterone and diabetes: What is the connection?


Obesity, especially abdominal obesity, induces low testosterone, which in turn predicts incident type 2 diabetes. Aging per se is not an independent cause of reduced total testosterone levels; the age-related drop in total testosterone is more strongly associated with obesity, particularly abdominal obesity (waist ≥ 100 cm).1

Obstructive sleep apnea (OSA) has a causal association with obesity and type 2 diabetes. It is commonly believed that OSA reduces testosterone levels. The question that arises is whether the association between OSA and low testosterone is mediated by obesity? Data show that after adjusting for obesity, the association between OSA and low testosterone disappears. Hence, OSA does not directly affect testosterone.

In obese men, weight loss dose-dependently increased testosterone levels.3 However, to increase testosterone levels by a degree that is clinically significant, a large weight loss is required, which is very hard to achieve and maintain.


Importantly, it should be noted that even intensive lifestyle interventions, such as the Diabetes Prevention Program which resulted in a weight loss of 7.97 kg after 1 year and increased endogenous testosterone from 10.98 nmol/L to 12.13 nmol/L (+1.15 nmol/L, 10% increase), did not significantly improve mood.4

A notable randomized controlled trial of diet+exercise vs diet+exercise+testosterone treatment showed that only testosterone treated patients had improvements in hypogonadal symptoms.5 Hence, weight loss alone does not necessarily improve symptoms related to hypogonadism.

Testosterone is an independent risk factor for progression to type 2 diabetes. Low testosterone especially predicts development of type 2 diabetes among men at high metabolic risk with increased waist circumference.

Currently underway is the T4DM trial, which investigates the effect of testosterone for type 2 diabetes prevention in men. Hypogonadal men aged 50-74 years with testosterone levels ≤14 nmol/L are given injectable testosterone undecanoate or placebo at baseline, 6 weeks and then every 3rd month thereafter for 2-4 years. More information can be found at www.DiabetesPrevention.org.au



Prof. Gary Wittert

Prof. Gary Wittert
Freemasons Foundation Centre for Men's Health
University of Adelaide, Australia


  • Shi Z, Araujo AB, Martin S, O'Loughlin P, Wittert GA. Longitudinal changes in testosterone over five years in community-dwelling men. J Clin Endocrinol Metab. 2013 Aug;98(8):3289-97. Return to content
  • Grossmann M. Low testosterone in men with type 2 diabetes: significance and treatment. J Clin Endocrinol Metab. 2011 Aug;96(8):2341-53. Return to content
  • Kim C, Barrett-Connor E, Aroda VR, et al. Testosterone and depressive symptoms among men in the Diabetes Prevention Program. Psychoneuroendocrinology. 2016;72:63-71. Return to content
  • Ng Tang Fui M, Hoermann R, Prendergast LA, Zajac JD, Grossmann M. Symptomatic response to testosterone treatment in dieting obese men with low testosterone levels in a randomized, placebo-controlled clinical trial. Int J Obes (Lond). 2017;41(3):420-426. Return to content