Effects of Testosterone Treatment on Body Fat and Lean Mass in Obese Men on a Hypocaloric Diet: A Randomised Controlled Trial

BMC Med. 2016 Oct 7;14(1):153. doi: 10.1186/s12916-016-0700-9.

Abstract

Background: Whether testosterone treatment has benefits on body composition over and above caloric restriction in men is unknown. We hypothesised that testosterone treatment augments diet-induced loss of fat mass and prevents loss of muscle mass.

Methods: We conducted a randomised double-blind, parallel, placebo controlled trial at a tertiary referral centre. A total of 100 obese men (body mass index ≥ 30 kg/m2) with a total testosterone level of or below 12 nmol/L and a median age of 53 years (interquartile range 47-60) receiving 10 weeks of a very low energy diet (VLED) followed by 46 weeks of weight maintenance were randomly assigned at baseline to 56 weeks of 10-weekly intramuscular testosterone undecanoate (n = 49, cases) or matching placebo (n = 51, controls). The main outcome measures were the between-group difference in fat and lean mass by dual-energy X-ray absorptiometry, and visceral fat area (computed tomography).

Results: A total of 82 men completed the study. At study end, compared to controls, cases had greater reductions in fat mass, with a mean adjusted between-group difference (MAD) of -2.9 kg (-5.7 to -0.2; P = 0.04), and in visceral fat (MAD -2678 mm2; -5180 to -176; P = 0.04). Although both groups lost the same lean mass following VLED (cases -3.9 kg (-5.3 to -2.6); controls -4.8 kg (-6.2 to -3.5), P = 0.36), cases regained lean mass (3.3 kg (1.9 to 4.7), P < 0.001) during weight maintenance, in contrast to controls (0.8 kg (-0.7 to 2.3), P = 0.29) so that, at study end, cases had an attenuated reduction in lean mass compared to controls (MAD 3.4 kg (1.3 to 5.5), P = 0.002).

Conclusions: While dieting men receiving placebo lost both fat and lean mass, the weight loss with testosterone treatment was almost exclusively due to loss of body fat.

Trial registration: clinicaltrials.gov, identifier NCT01616732 , registration date: June 8, 2012.

Keywords: Body composition; Caloric restriction; Obesity; Testosterone.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Absorptiometry, Photon
  • Adipose Tissue / drug effects
  • Body Composition / drug effects
  • Body Weight / drug effects
  • Combined Modality Therapy / methods*
  • Diet, Reducing / methods*
  • Double-Blind Method
  • Humans
  • Male
  • Middle Aged
  • Obesity / diet therapy*
  • Obesity / drug therapy*
  • Testosterone / administration & dosage
  • Testosterone / analogs & derivatives*

Substances

  • Testosterone
  • testosterone undecanoate

Associated data

  • ClinicalTrials.gov/NCT01616732