Two tennis players suspended after testing positive for banned substance clostebol

While most of the tennis headlines are stemming from the ongoing Rome Open with the 1000 tournament heading into the business end, there is other significant news away from the Italian capital. The International Tennis Integrity Agency has confirmed that two players have been provisionally suspended following a positive test for the banned substance clostebol.

Karlis Ozolins of Latvia and Daniil Kakhniuk of the USA were both competing in the ITF World Tennis Tour event in San Jose, Costa Rica, on February 17 when these samples were provided to them. While under suspension, they cannot compete, coach or attend any events organised by the ATP, WTA, ITF, the four Grand Slams, or any national association,

Ozolins had a career high ranking of world number 618. He has played six matches at ATP level, winning two and losing four. He has not competed since March when he won the M15 Maanshan ITF event. He was a semi-finalist in San Jose. Kakhniuk is coming off the back of reaching a career high 1112 in the world earlier this year. He last stepped onto the court at the ITF M25 event in Las Vegas, qualifying before losing in the second round.

Both of these contained metabolites of clostebol. This is a synthetic anabolic-androgenic steroid which is classed as a classed as a non-Specified substance and considered a performance-enhancing substance, thus being banned by WADA and in the Tennis Anti-Doping Programme.

The ITIA were forced to make the decision over suspending the two individuals. A statement read: “because of the nature of the substance, a provisional suspension is mandatory.” The suspensions have been implemented from April 14. No appeal over the suspensions have occurred yet.

The anti-doping programme reads: “Where a Notice is issued to a Player based on an Adverse Analytical Finding or Adverse Passport Finding for a Prohibited Substance that is not a Specified Substance or for Use of a Prohibited Method that is not a Specified Method, then (subject only to Article 7.12.3) a Provisional Suspension will come into effect automatically on the date specified by the ITIA in the Notice or in further correspondence up to and including the Charge Letter.”

In line with the anti-doping programme, both men will have support available. “As with all Tennis Anti-Doping Programme cases, ITIA support is available to both players, including pro-bono legal aid, independent wellbeing support, and financial assistance to investigate the source of positive findings."

Clostebol has been a common method used by tennis players to get the edge on court. Many tennis players have fallen afoul of the rules, including world number one Jannik Sinner. He had tested positive for the substance back in March 2024, with the case dragging on for some time.

Just under a year later, a three month ban was put in place right after he defended his Australian Open title. The Italian missed out on the Sunshine swing and the first part of the clay season, returning for his home event in Rome. While the four-time Grand Slam champion boasts the most famous case surrounding the banned substance, many more tennis players have been caught with it.