Horm Metab Res 2011; 43(3): 223-225
DOI: 10.1055/s-0030-1269854
Short Communication

© Georg Thieme Verlag KG Stuttgart · New York

Effect of Vitamin D Supplementation on Testosterone Levels in Men

S. Pilz1 , [*] , S. Frisch2 , [*] , H. Koertke2 , J. Kuhn3 , J. Dreier3 , B. Obermayer-Pietsch1 , E. Wehr1 , A. Zittermann2
  • 1Department of Internal Medicine, Division of Endocrinology and Metabolism, Medical University of Graz, Austria
  • 2Clinic for Thoracic and Cardiovascular Surgery, Heart Centre North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany
  • 3Institute for Laboratory and Transfusion Medicine, Heart Centre North Rhine-Westphalia, Ruhr University Bochum, Bad Oeynhausen, Germany
Further Information

Publication History

received 04.08.2010

accepted 03.11.2010

Publication Date:
10 December 2010 (eFirst)

Abstract

The male reproductive tract has been identified as a target tissue for vitamin D, and previous data suggest an association of 25-hydroxyvitamin D [25(OH)D] with testosterone levels in men. We therefore aimed to evaluate whether vitamin D supplementation influences testosterone levels in men. Healthy overweight men undergoing a weight reduction program who participated in a randomized controlled trial were analyzed for testosterone levels. The entire study included 200 nondiabetic subjects, of whom 165 participants (54 men) completed the trial. Participants received either 83 μg (3 332 IU) vitamin D daily for 1 year (n=31) or placebo (n=23). Initial 25(OH)D concentrations were in the deficiency range (<50 nmol/l) and testosterone values were at the lower end of the reference range (9.09–55.28 nmol/l for males aged 20–49 years) in both groups. Mean circulating 25(OH)D concentrations increased significantly by 53.5 nmol/l in the vitamin D group, but remained almost constant in the placebo group. Compared to baseline values, a significant increase in total testosterone levels (from 10.7±3.9 nmol/l to 13.4±4.7 nmol/l; p<0.001), bioactive testosterone (from 5.21±1.87 nmol/l to 6.25±2.01 nmol/l; p=0.001), and free testosterone levels (from 0.222±0.080 nmol/l to 0.267±0.087 nmol/l; p=0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group. Our results suggest that vitamin D supplementation might increase testosterone levels. Further randomized controlled trials are warranted to confirm this hypothesis.