Effects of vitamin D supplementation on androgens in men with low testosterone levels: a randomized controlled trial

Eur J Nutr. 2019 Dec;58(8):3135-3146. doi: 10.1007/s00394-018-1858-z. Epub 2018 Nov 20.


Purpose: It has been hypothesized that vitamin D is associated with androgen levels in men. We, therefore, aimed to evaluate whether vitamin D supplementation increases serum total testosterone (TT) levels in men with low TT levels at baseline.

Methods: The Graz Vitamin D&TT-RCT is a single-center, double-blind, randomized placebo-controlled trial conducted between March 2013 and November 2017 at the endocrine outpatient clinic at the Medical University of Graz, Austria. One-hundred healthy men with serum TT levels < 10.4 nmol/l and 25-hydroxyvitamin D [25(OH)D] levels < 75 nmol/l participated in the trial. Subjects were randomized to receive 20,000 IU of vitamin D3/week (n = 50) or placebo (n = 50) for 12 weeks. Primary outcome was TT measured using mass spectrometry. Secondary outcomes were free testosterone, free androgen index, sex hormone-binding globulin, estradiol, follicle-stimulating hormone, luteinizing hormone, metabolic characteristics, and body composition.

Results: Ninety-four men [mean age and 25(OH)D: 47 (± 12) years and 56.3 (± 18.3) nmol/l, respectively] completed the study. We found no significant treatment effect on serum TT or on the remaining secondary outcome variables.

Conclusion: Vitamin D treatment had no effect on serum TT levels in middle-aged healthy men with low TT levels.

Keywords: Androgens; Randomized controlled trial; SHBG; Testosterone; Vitamin D.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Androgens / blood*
  • Austria
  • Dietary Supplements*
  • Double-Blind Method
  • Humans
  • Male
  • Middle Aged
  • Testosterone / blood*
  • Vitamin D / administration & dosage*
  • Vitamin D / blood*
  • Vitamins / administration & dosage
  • Vitamins / blood


  • Androgens
  • Vitamins
  • Vitamin D
  • Testosterone

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