Usain Bolt has insisted his fans can have complete confidence that he is 100% clean after the drug scandals involving two of his leading rivals.
The Jamaican was forced to defend his record-breaking achievements after his compatriot Asafa Powell and American Tyson Gay tested positive, plunging the sport into its biggest credibility crisis in years.
Bolt, the world record holder and Olympic champion of the 100 and 200 metres, insisted those who had followed his career from before he became a household name would know he was clean.
He said: "If you were following me since 2002 you would know that I have been doing phenomenal things since I was 15.
"I was the youngest person to win the world junior title at 15, I ran the world junior record at 18, the world youth record at 17. I have broken every record there is to break, in every event I have ever done. For me, I have proven myself since I was 15.
"For me, I have shown I was always going to be great."
He added: "I was made to inspire people and to run. I was given a gift and that's what I do. I am confident in myself and my team, the people I work with. And I know I am clean."
Gay and Powell, the second and fourth fastest men in history, are still waiting for the results of their 'B' samples, and Bolt said it was important not to speculate too much at this stage.
"I think there are a lot of details left to be discussed," he said.
Powell's failed test for the banned stimulant oxilofrine has been blamed by his camp on new nutritional supplements he had been taking.
Bolt said he did not take any supplements, saying: "I take vitamins, every athlete takes vitamins."
The 26-year-old revealed he had been in contact with Powell by text since the news of the failed test broke and told him to "stay strong and stay focused. I didn't want to bombard him with questions. I told him, 'Sorry to hear what was going on' and he said, 'Yes, it's kind of rough, it's hard."
Powell has claimed he did not knowingly take the banned substance and Bolt emphasised the need for athletes to make sure they know what they are ingesting.
"You have to be very careful as an athlete, because right now there are a lot of things on the banned list," he added.
"You might not know and you have to keep up to date with this kind of thing. It's kind of hard, but that's why you have a team to make sure."
Powell's manager, Paul Doyle, has pointed the finger of blame for his failed test at their trainer, Canadian Chris Xuereb, who only began working with him in May.