Great Britain were stripped of the silver medal they won in the 4x100m relay at the 2020 OlympicsBritish sprinter CJ Ujah has been banned for 22 months after he tested positive for two banned substances at the Tokyo Olympics.
However, he has been cleared of intentionally taking prohibited drugs by the Athletics Integrity Unit (AIU) and World Anti-Doping Agency (WADA).
Britain was stripped of its Olympic men's 4x100m silver medal after Ujah tested positive for Ostarine and S-23.
The ban is backdated to 6 August 2021 and will end on 5 June 2023.
The AIU and WADA ruled that the sprinter's anti-doping rule violation (ADRV) was not intentional and it was instead a result of his ingestion of a contaminated supplement.
The applicable two-year period of ineligibility was reduced by two months on account of the 28-year-old's prompt admittance of the violation.
"In this case, after a thorough examination of the facts, we were satisfied that Mr Ujah did indeed ingest a contaminated supplement, but he was unable to demonstrate that he was entitled to any reduction in the applicable period of ineligibility based on his level of fault," said AIU Head Brett Clothier.
Clothier added: "Taking supplements is risky for athletes as they can be contaminated or even adulterated with prohibited substances.
"Athletes owe it to their fellow competitors to be 100 per cent certain before putting anything into their body. If there's the slightest doubt, leave it out."
UK Athletics (UKA) expressed its "extreme disappointment, frustration and sadness" towards Ujah's actions.
"The negligence of one individual to fulfil their commitment to clean athletics - one of the essential obligations of representing Great Britain and Northern Ireland - had a devastating impact upon the entire relay programme, but none more so than the other athletes who competed alongside Ujah in the Olympic final," added UKA.
"The sanction handed down to CJ Ujah, suspending him from competing within the sport, the resulting impact upon his team-mates and their families and support networks, as well as the huge disappointment to GB and NI team fans, reinforces the importance of clean sport."
At the time of the positive test, Ujah said he had "unknowingly consumed a contaminated substance" and the situation is one he would "regret for the rest of my life".
Ujah apologised to his 4x100m relay team-mates Zharnel Hughes, Richard Kilty and Nethaneel Mitchell-Blake, after Britain was stripped of a medal at a summer or winter Games for only the third time.
Following the news, Kilty said it was "absolutely heartbreaking" to have been stripped of the medal and added the rules athletes must follow are "hammered home" by British Athletics and UK Anti-Doping.
"It's just devastating that other team-mates haven't followed the rules as strictly as the rest of us," said Kilty. "We've been burned by that."
Ujah did not not challenge the decision over his violation, made by the Anti-Doping Division of the Court of Arbitration for Sport (Cas).
Ostarine and S-23 are Selective Androgen Receptor Modulators (SARMS) and the UK Anti-Doping website states Ostarine is a drug designed to have similar effects to Testosterone.
The ruling by the AIU and WADA means Ujah will return to competition in time for the 2023 World Championships in Budapest next August.
