Botswana's Nijel Amos returned a positive test for the banned metabolite GW1516 ©Getty Images

Olympic silver medallist Nijel Amos has been provisionally suspended by the Athletics Integrity Unit after testing positive for a banned metabolite.

The Botswanan middle-distance runner had been set to compete at the World Athletics Championships in Eugene, due to begin on Friday (July 15).

The sample in question was taken in an out-of-competition test on June 4, and returned an adverse analytical finding for metabolites of GW1516.

GW1516 is on the 2022 World Anti-Doping Agency (WADA) Prohibited List as a metabolic modulator, a category which covers substances that modify how the body metabolises fat.

It was originally developed to treat obesity, diabetes and other disorders caused by metabolic problems.

It was pulled from clinical trials after being found to cause cancer, and WADA has warned of the health risks posed by its usage.

Nijel Amos won Botswana's first Olympic medal with a silver in the men's 800m at London 2012 ©Getty Images
Nijel Amos won Botswana's first Olympic medal with a silver in the men's 800m at London 2012 ©Getty Images

Amos won silver in the men's 800 metres at London 2012, which was Botswana's first Olympic medal, and followed it with gold in the same race at the Glasgow 2014 Commonwealth Games.

He ran a world-leading 1min 42.91sec in Monaco in July last year prior to Tokyo 2020, but missed out on a medal at the Olympics as he placed eighth in the final, which he reached on appeal after a collision with the United States' Isaiah Jewett in the semi-final.

At the Diamond League meeting in Rabat last month, Amos finished second behind Kenya's Emmanuel Wanyonyi.

Amos had been due to compete in the 800m heats at the World Athletics Championships next Wednesday (July 20).