Statistical significance of hair analysis of clenbuterol to discriminate therapeutic use from contamination

Drug Test Anal. 2014 Nov-Dec;6(11-12):1108-16. doi: 10.1002/dta.1746. Epub 2014 Nov 11.


Clenbuterol is a well-established β2-agonist, which is prohibited in sports and strictly regulated for use in the livestock industry. During the last few years clenbuterol-positive results in doping controls and in samples from residents or travellers from a high-risk country were suspected to be related the illegal use of clenbuterol for fattening. A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to detect low clenbuterol residues in hair with a detection limit of 0.02 pg/mg. A sub-therapeutic application study and a field study with volunteers, who have a high risk of contamination, were performed. For the application study, a total dosage of 30 µg clenbuterol was applied to 20 healthy volunteers on 5 subsequent days. One month after the beginning of the application, clenbuterol was detected in the proximal hair segment (0-1 cm) in concentrations between 0.43 and 4.76 pg/mg. For the second part, samples of 66 Mexican soccer players were analyzed. In 89% of these volunteers, clenbuterol was detectable in their hair at concentrations between 0.02 and 1.90 pg/mg. A comparison of both parts showed no statistical difference between sub-therapeutic application and contamination. In contrast, discrimination to a typical abuse of clenbuterol is apparently possible. Due to these findings results of real doping control samples can be evaluated.

Keywords: clenbuterol; doping; food contamination; hair.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adrenergic beta-2 Receptor Agonists / analysis*
  • Adrenergic beta-2 Receptor Agonists / therapeutic use*
  • Adult
  • Bicycling
  • Clenbuterol / analysis*
  • Clenbuterol / therapeutic use*
  • Doping in Sports*
  • Female
  • Food Contamination
  • Hair / chemistry*
  • Humans
  • Indicators and Reagents
  • Male
  • Mexico
  • Reference Standards
  • Reproducibility of Results
  • Soccer
  • Young Adult


  • Adrenergic beta-2 Receptor Agonists
  • Indicators and Reagents
  • Clenbuterol