Pereira, H. M., Marques, M. A., Talhas, I. B., & Aquino Neto, F. R. (2004). Incidental Clostebol contamination in athletes after sexual intercourse. Clinical Chemistry, 50, 456-457.

An athlete tested positive at LABDOP (Drug-testing Laboratory in Brazil) for Clostebol after having sexual intercourse with a partner using a medication containing Clostebol. The IOC decreed such an individual should be punished under the anti-doping code.

To verify and understand this phenomenon better, an investigation was performed.

In Brazil, Clostebol acetate is available for intravaginal administration. Two healthy couples (group I) and two healthy men (group II) were involved in the study. A baseline urine sample was obtained before exposure to Clostebol acetate. Ss were healthy and without a history of drug use or gynecologic disease. Immediately after intravaginal application of 5 g of Clostebol acetate, group I had sexual intercourse lasting 20 minutes (experiment I). In experiment II, the men applied 200 mg of Clostebol acetate topically to their penises for 20 minutes. Urine samples were collected from all participant volunteers for the following two days.

The urine of the men in experiment I contained trace amounts of Clostebol-M1 (0.9–3.5 µg/L) for up to a maximum of 16 hours after exposure. The concentration of Clostebol-M1 in the urine of the females reached a maximum of 35 µg/L after 23 hours. Small amounts of Clostebol-M2 were also detected. The urine of the men in experiment II contained higher amounts of Clostebol-M1, with a peak concentration of 22 µg/L after 3.5 hours. The substance was detectable for 15 hours. The baseline urines contained no Clostebol, Clostebol-M1, or Clostebol-M2. The possibility of incidental contamination from sexual intercourse was confirmed, despite the fact that the amount of Clostebol-M1 (long-term metabolite) was near the limit of detection (µg/L).

Implication. Because the IOC does not consider circumstances or means of administration of anabolic compounds, athletes should be warned not to use Clostebol-containing medications and to be aware of their partner’s medical treatments. If that warning is not heeded, a positive test result would lead to branding the athlete in question as a "drug cheat".

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