British sprinter CJ Ujah has been suspended from competition after testing positive for a banned substance.
Ujah, 27, was part of Team GB men’s 4x100m relay team which won silver at the Tokyo 2020 Olympics this month.
He has been provisionally suspended, said the Athletics Integrity Unit (AIU).
The AIU said a test showed the “presence/use of a prohibited substance (Ostarine and S-23).”
A UK Athletics spokesperson said the governing body does not comment on ongoing processes.
Ujah, who has yet to comment, won the 100m at the British Championships in June.
Britain’s men’s quartet missed out on the 4x100m title by just a hundredth of a second in Tokyo, as anchor leg runner Nethaneel Mitchell-Blake was overhauled on the line by Italy’s Filippo Tortu.
The International Testing Agency (ITA) said: “The Anti-Doping Division of the Court of Arbitration for Sport [CAS] will consider the matter of the finding of an Anti-Doping Rule Violation [ADRV] and the disqualification of the men’s 4 x 100 relay results of the British team”.
Enobosarm, or Ostarine, is listed as an anabolic agent – banned at all times – in the World Anti-Doping Agency’s list of prohibited substances.
The UK Anti-Doping (Ukad) website said it has “similar effects to testosterone”.
Three other athletes have been suspended after tests carried out during the Tokyo Olympics.
They are Moroccan 1500m runner Sadik Mikhou, shot putter Benik Abramyan of Georgia and Kenyan sprinter Mark Otieno Odhiambo.
More to follow.