The 26-year-old won bronze in the Brazilian city behind British brothers Alistair and Jonathan Brownlee and also won the final leg of the 2016 ITU World Championship Series in Cozumel.

Alleged leaks of internal International Olympic Committee (IOC) emails by Russian-linked hacking group Fancy Bears, published by the Sputnik news agency, indicated that he failed a test for banned performance-enhancing substance glucocorticoid prednisolone.

This is prohibited only "when administered by oral, intravenous, intramuscular or rectal routes".

Athletes are permitted to apply the substance to specific areas to deal with skin rashes, or can apply for a therepeutic use exemption (TUE) allowing wider use.

The leaked emails appeared to show that the use of the otherwise-banned product was declared on Schoeman's anti-doping control form, leading the IOC medical and scientific director Richard Budgett to seemingly ask whether a "retroactive TUE" would be accepted.

There was no information of any sort of violation by Schoeman announced at the time. 

The ITU has now thanked Schoeman and said the IOC would be investigating the circumstances of the leak.

"Following the investigation opened by ITU and the IOC over the publication on some media outlets of allegations involving Henri Schoeman and an adverse analytical finding (AAF) that would have occurred during the 2016 Rio Olympic Games, all parties involved want to declare that the case was not considered to be any anti-doping rule violation," an ITU statement said.

"The result management went in accordance with the World Anti-Doping Agency rules and the process concluded that no AAF was recorded. 

"As a result, the case was not considered to be, nor did it result in, an anti-doping rule violation.

"ITU wants to acknowledge and thank Mr. Henri Schoeman, who has been fully cooperative, providing any information to both the IOC and to ITU during this investigation process, since the information was publicly disclosed."

Schoeman said on his official website that "what he knew all along" had been proven.

"There have been many hurtful comments and judgements passed on my character in the past week, yet I count myself fortunate to have the support and encouragement of my family, friends and fans," he said.

"I am happy to put this behind me and will continue to put in the hard work and focus on my preparation for the Commonwealth Games in April as well as the 2018 World Triathlon Series season.

"I have never failed a drug test in my sporting career nor have I ever had to apply for a TUE."

Marisol Casado, the President of the ITU and also an IOC member, added that her organisation "strongly believed" in clean sport.

"We feel extremely satisfied that this investigation is completely closed and clears the name of an athlete who has been cooperative, supportive and always assisted ITU and the IOC to clarify these circumstances, even under a lot of pressure," the Spaniard said. 

"The professionalism and openness shown by Henri Schoeman should be an example for any athlete that could face a situation like this."

The IOC is said to "strongly condemn" unlawful attempts to disclose confidential information and will prosecute if necessary. 

The IOC, rather than the ITU, were responsible for administering doping cases during Rio 2016.