What is clostebol, a substance that banned many athletes?

Clostebol, a mild anabolic steroid that has really got on the radar since 2016 when high profile athletes started testing positive for the substance.

Clostebol is getting more and more attention. And not for the good thing. The steroid has sidelined high profile sports persons in baseball, swimming, cross-country skiing, tennis and and soccer. In this article we will try and answer questions regarding this substance

What is Clostebol?

Clostebol, also known as 4-chlorotestosterone, is a mild anabolic steroid that mimics testosterone but does not break down into estrogen. It is classified as a Non-Specified substance and is prohibited under category S1 of the 2021 WADA Prohibited List.
Clostebol was initially developed in East Germany. It has gained attention in recent years due to its use in doping cases in various sports.

What is clostebol used for?

In a medical context, Clostebol is prescribed to treat conditions such as muscle wasting, androgen deficiency, and delayed puberty. It is also used for treating minor skin wounds

However, its use for athletic performance improvement is strictly prohibited and considered as doping. This is also the main objective of Clostebol. It was developed as a doping drug in the 1970s-1980s to make Eastern German athletes perform better.

The doping advantage of injectable clostebol is that, while less potent, it mimics the muscle-building properties of testosterone without the estrogen buildup that counteracts them.

One of the reasons why Clostebol is used by athletes is that it keep stestosterone levels high, estrogen low, and leaves little trace. This is a good combination for anyone trying to build more muscle.

Clostebol is on the prohibited substance list

Clostebol is classified as a Non-Specified substance under category S1 of the 2021 WADA Prohibited List. Its use in sports is strictly prohibited, and positive tests for clostebol carry a mandatory Provisional Suspension.

Anti-doping tests can easily isolate and identify the presence of clostebol. Advanced testing methods can detect even trace amounts of the substance, ensuring effective detection and prevention of its misuse.

As for popularity, Clostebol isn't wildly used. In the Anti-Doping Database it is on place 50 of cases involving Anabolic Steroids. A list that is topped by Stanozolol with more than 1200 doping violations.

Several athletes have tested positive for clostebol. Notable cases include Olympic athlete Viktoria Orsi Toth (Italy), Serie A soccer player José Luis Palomino (Club Atalanta), Serie A soccer player Orji Okonkwo (Nigeria), cross-country skier Therese Johaug (Norway), swimmer Joanna Evans (Bahamas) and MLB-player Fernando Tatis Jr.

Many athletes suspended

Besides the mentioned publicly known athletes, the Anti-Doping Database has registered 63 doping cases involving clostebol. As of July 2023.

Cycling has had the highest number of cases (13), followed by soccer (8) and track and field (7). The substance's use spans across different athletic disciplines.
Normally Clostebol causes around 6 doping bans per year. In 2016 how ever, the number of banned athletes spiked to 10.

Doping violations related to clostebol carry significant sanctions. In the registered cases, a 2-year suspension has been imposed in 15 instances, a 1-year suspension in 13 cases, and a 4-year suspension in 10 cases. These penalties reflect the severity of the offense.

Clostebol in Italy

The misuse of clostebol has been growing in certain countries, notably Italy, attributed to the ample availability of pharmaceutical formulations containing clostebol acetate (Trofodermin®). Additionally, the use of more sensitive instrumentation in anti-doping laboratories has facilitated the detection of the substance, leading to increased cases.

It was in Italy the Norwegian cross-country skier Johaug bought the cream Trofodermin containing Clostebol which caused a long ban from sport.

Remember, the use of Clostebol and any other performance-enhancing drugs is strictly forbidden in sports. To ensure clean, fair, and safe competitions, athletes should adhere to anti-doping regulations and compete based on their natural abilities and talents.

Disclaimer: This FAQ is provided for informational purposes only and is not a substitute for professional medical advice. Always consult with a qualified healthcare provider before using any medication or supplement.


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Any use of the information should quote the Anti-Doping Database.

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