title: Serum testosterone and urinary excretion of steroid hormone metabolites after administration of a high-dose zinc supplement.
abstract: OBJECTIVE
  To investigate whether the administration of the zinc-containing nutritional supplement ZMA causes an increase of serum testosterone levels, which is an often claimed effect in advertising for such products; to monitor the urinary excretion of testosterone and selected steroid hormone metabolites to detect potential changes in the excretion patterns of ZMA users.
  
  
  METHODS
  Fourteen healthy, regularly exercising men aged 22-33 years with a baseline zinc intake between 11.9 and 23.2 mg day(-1) prior to the study.
  
  
  RESULTS
  Supplementation of ZMA significantly increased serum zinc (P=0.031) and urinary zinc excretion (P=0.035). Urinary pH (P=0.011) and urine flow (P=0.045) were also elevated in the subjects using ZMA. No significant changes in serum total and serum free testosterone were observed in response to ZMA use. Also, the urinary excretion pattern of testosterone metabolites was not significantly altered in ZMA users.
  
  
  CONCLUSIONS
  The present data suggest that the use of ZMA has no significant effects regarding serum testosterone levels and the metabolism of testosterone in subjects who consume a zinc-sufficient diet.
authors: Institute of Biochemistry, German Research Centre of Elite Sport, German Sport University Cologne, Cologne, Germany. k.koehler@biochem.dshs-koeln.de
authors: K
authors: K
authors: Koehler
authors: M K
authors: MK
authors: Parr
authors: H
authors: H
authors: Geyer
authors: J
authors: J
authors: Mester
authors: W
authors: W
authors: Schänzer
mesh_terms: D000328:Adult; D000728:Androgens / Q000097:blood / Q000378:metabolism*; D019587:Dietary Supplements; D004338:Drug Combinations; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D013739:Testosterone / Q000097:blood / Q000378:metabolism* / Q000652:urine; D014554:Urination / Q000187:drug effects; D014556:Urine / Q000737:chemistry; D025101:Vitamin B 6 / Q000494:pharmacology; D055815:Young Adult; D015032:Zinc / Q000097:blood / Q000494:pharmacology* / Q000652:urine
chemical_list: D000728:Androgens; D004338:Drug Combinations; D013739:Testosterone; D025101:Vitamin B 6; D008274:Magnesium; D015032:Zinc