Clostebol and Consequences: Will Jannik Sinner Face a Ban?
February 04, 2025Jannik Sinner’s doping case has ignited debate over how sporting authorities handle accidental ingestion claims. With trace amounts of Clostebol found in his system, the Italian tennis star insists he is innocent. But with past cases yielding vastly different outcomes, all eyes are now on the Court of Arbitration for Sport as it prepares to rule on his fate.
The Italian tennis-player Jannik Sinner was selected for doping test on March 10, 2024. Sinner was participating in the tennis tournament BNP Paribas Open in Indian Wells in the USA. Five days later, during the Miami Open, a second sample was collected.
Both samples came back positive for Clostebol, but in very low concentration – 121pg/mL (picogram per milliliter) and 122pg/mL. These values were later adjusted to 86pg/mL and 76pg/mL. converted to nanogram we’re talking 0,76ng and 0,86ng.
Sinner claims the substance entered his body through his physiotherapist – Giacomo Naldi. The physio had cut himself and had treated the cut with the medical spray with the brand name “Trofodermin”. The medical spray contains Clostebol.
He was cleared by the International Tennis Integrity Agency (ITIA).
Comparable case 1 - Dominika Jamnicky
After returning from the Commonwealth Games in Australia in 2018, Dominika Jamnicky – a triathlete from Canada - was tested out-of-competition administered by the Canadian Center for Ethics in Sport (CCES).
The sample was sent to a WADA accredited laboratory in Quebec for analysis. The analysis showed traces of clostebol estimated at a concentration of 0.15 ng/mL or 0.2ng/mL. Less than what was found in the samples collected from Sinner.
Jamnicky was cleared by the Canadian Tribunal, but CCES appealed the decision to the Court of Arbitration for Sport (CAS).
CAS came to the following conclusion: Jamnicky is found to have commited an Anti-Doping Rule Violation, but bears no fault of negligence and no period of ineligibiliy shall be imposed on her.
Comparable case 2 – Therese Johaug and medication
Many has compared Sinners case against the Norwegian cross-country skier Therese Johaug. The Norwegian athlete was tested out-of-competition after coming back from a training camp in Italy.
The sample was analysis and the result was positive for Clostebol. Her concentration of the prohibited substances was 13ng/mL.
Johaug was suspended for 18 months after the World Anti-Doping Agency and the International Ski Federation (FIS) appealed the decision to CAS. Originally Johaug was suspended for 13 months by the Adjudication Committee of the Norwegian Olympic and Paralympic Committee and Confederation of Sport.
Comparable case 3 – Alberto Contador and contaminated food
Back in 2010 the Spanish pro cyclist Alberto Contador was competing in the Tour de France – one of the Grand Tours in cycling. On July 21, 2010 – a rest day following the 16th stage of the race, the International Cycling Union submitted Contador to a urine test.
The sample collected was analyzed at the WADA-accredited Laboratory for Doping Analysis – German Sports University Cologne in Cologne, Germany. The analysis contained clenbuterol in a concentration of 50pg/mL. This is less than what was found in the sample collected from Sinner.
But Clenbuterol is a much different steroid than Clostebol. Clenbuterol is a much stronger and more effective steroid than Clostebol.
Contador claimed he had gotten the banned substance in his body through contaminated meat. His defense was not believed and even after appealing to CAS, the Spanish cyclist was banned for two years.
What does our database show?
· We have registered 76 doping cases involving Clostebol
· Italy (26), Brazil (8) and Costa Rica (5) are the top three countries.
· Cycling (15), Soccer (8) and Athletics (7) are the top three sports. Tennis comes in 4th position with six.
· Sanctions: 3 athletes has been given no (significant) fault or negligence – no suspension, 16 athletes has been banned for two years, 14 for four years. Four has been banned for three years.
24 in total has been banned for less than two years – 14 of these for one year.
What type of sanction can Sinner expect?
There is a lot of speculations on what sanction Sinner may end up getting. Looking at the statistics he can receive anything from no fault of negligence to around one year.
Sinner has claimed the substance entered his body through his physiotherapist. The latter had some days prior cut his finger and used a medicine to treat the cut. The medicine contained Clostebol.
In the legal papers from ITIA, Sinner claims he asked the physiotherapist if he had used anything to treat the injury. Naldi had answered no to that question.
Naldi also claims he didn’t know the spray contained a banned substance. He had been given the medicine from Sinners fitness coach who in turn had bought the spray at a pharmasy in Italy.
This is a difficult case. The legal papers shows clearly that Sinner has done what is expected of him to make sure no prohibited substance enters his body. He saw that his physiotherapist had been injured. Sinner had asked if the physio had used anything to treat it, and the physio had said no he hadn’t used anything – even though he had.
The Court of Arbitration for Sport (CAS) now has to decide if they believe the story from Sinner and the people around him or not. If they do, Sinner will most likely get the same verdict as he got in the ITIA tribunal. If they don’t, the Italian tennis player will get a suspension. How long? Hard to say. By looking at our data in the Anti-Doping Database, a sanction around 12 months is not unlikely.
How has the positive test impacted Sinner
The Anti-Doping Database is subscribing to Google News Alerts and we store the information in a database. Our data shows that there has been written more than 700 articles where the words Sinner and Doping is being mentioned.
In August in 2024 there were written close 120 articles. The following month 160 articles about Sinner where doping was mentioned were published.
Google Alerts do not cover all media outlets, so the number of articles on Sinner in relation with doping is most likely higher.