Great Britain lost their 4×100 metres silver medal from the Tokyo Olympics when Ujah tested positive for two prohibited substances.
However, Ujah, 28, was found not to have breached the sport's doping rules on purpose.
Ujah was tested on the day of the final in Tokyo - August 6 - and his sample contained the prohibited substances ostarine and S-23.
He will be allowed to return to competition when his ban ends in June of next year.
"Obviously, I made a mistake," Ujah told The Guardian. "But people mistakes. I am not a cheat.
"I think complacency set in. During the (coronavirus) pandemic I relied a lot on Amazon, rather than using the people and resources around me. It was just convenient, with next-day delivery. And I didn't think anything was wrong with it."
Ujah was part of the British quartet, along with Zharnel Hughes, Nethaneel Mitchell-Blake and Richard Kilty, which missed out on gold to Italy in Tokyo by 0.01 seconds.
"You know what? I wish I had been tested right before the Olympics, so that I never went," Ujah added.
"That way, I would never have put these other three guys, my team-mates, through what they went through as well as myself."
Speaking earlier this year, Kilty said he would never be able to forgive his former team-mate.
"What he (Ujah) has done has been reckless," Kilty said. "Everything has been a team effort to get to that position to be part of the British 4×100 strike four.
"Now he's made that mistake I don't think I'll ever be able to forgive him because me, Zharnel and Nethaneel have lost a medal at the hands of his mistakes."
Responding to Kilty's comments, Ujah said: "Reckless is a harsh word. I saw the criticism from Kilty and I can't blame him.
"He's got a family. He's got kids. So I do sympathise with him and understand the position he's coming from."
The Athletics Integrity Unit and World Anti-Doping Agency said in a statement they were "satisfied that the sprinter's anti-doping rule violation (ADRV) was not intentional as a result of his ingestion of a contaminated supplement".
They added that "the applicable two-year period of ineligibility was reduced by two months on account of how promptly he admitted the violation".
AIU head Brett Clothier said: "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.
"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."