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.


29 October 2020
Botrè, Francesco
Colamonici, Cristiana
de la Torre, Xavier
Iannone, Michele
Jardines, Daniel
Molaioni, Francesco
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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
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Person-to-person transfer
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Date generated
22 February 2021
Date of last modification
3 March 2021
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