Detection of clostebol in sports: Accidental doping?

Detection of clostebol in sports : Accidental doping? / Xavier de la Torre, Cristiana Colamonici, Michele Iannone, Daniel Jardines, Francesco Molaioni, Francesco Botrè. - (Drug Testing and Analysis 12 (2020) 11-12 (November-December); p. 1561-1569). - Special Issue: The 38th Manfred Donike workshop on doping analysis

  • PMID: 33119965
  • DOI: 10.1002/dta.2951


The detection of clostebol misuse in sports has been growing recently, especially in Italy, due to the ample availability of pharmaceutical formulations containing clostebol acetate (Trofodermin®) and the use of more sensitive instrumentation by the antidoping laboratories. Most of these cases have been claimed to be related to a nonconscious use of the drug or through contact with relatives or teammates using it. We have investigated, through the application of the well-known and currently used gas chromatographic mass spectrometric procedures, the likelihood of these allegations and have demonstrated that after a single transdermal administration of 5 mg of clostebol acetate and a transient contact with the application area, it is possible to generate adverse analytical findings in antidoping controls. We have reviewed the Phase I and Phase II clostebol metabolism in order to generate evidences that may help the sport authorities reviewing these cases. The main clostebol metabolite (4-chloro-androst-4-en-3α-ol-17-one, M1) generally used at the screening level as well as other three metabolites (M2-M4) are mainly excreted as glucuronides, whereas M5 (4ζ-chloro-5ζ-androstan-3β-ol-17-one) is predominantly excreted as sulfate. Neither the 5α-reductases activity (impaired by the presence of the chlorine in C4) nor specific sulfotransferases present in the skin allowed a clear distinction of the administration route. Studies with a larger number of volunteers and probably investigating another physiological fluid allowed in antidoping such as blood are needed for a deeper investigation. It is not unreasonable to establish a reporting level for M1, maybe creating some false negatives but excluding nonintentional doping scenarios.


Research / Study
29 October 2020
Botrè, Francesco
Colamonici, Cristiana
de la Torre, Xavier
Iannone, Michele
Jardines, Daniel
Molaioni, Francesco
Other organisations
Sapienza Università di Roma - Sapienza University of Rome
Roma, Italia: Laboratorio Antidoping FMSI
Analytical aspects
Mass spectrometry analysis
Testing method development
Doping classes
S1. Anabolic Agents
Medical terms
Person-to-person transfer
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Date generated
22 February 2021
Date of last modification
3 March 2021
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