Former Olympic champion Asbel Kiprop has given up the fight to clear his name over a positive doping sample.
The Kenyan middle-distance runner was found to have traces of EPO in his system after a test in November 2017 but maintained the sample had been tampered with by officials.
Kiprop wrote in a Facebook post: "I have let the struggle to prove my innocence go.
"Not because I doped but I take the sacrifice because I support the anti-doping campaign."
The 28-year-old had previously admitted giving money to drug testers out of "generosity" but claimed he was punished because he did not pay them enough.
Kiprop won the silver medal in the 1500m at the Beijing Olympics in 2008 but was upgraded to gold when Bahrain's Rashid Ramzi failed a drugs test.