Norwegian sprinter Aham Okeke has received a lifetime ban from competition after confessing to using the male sex hormone testosterone, anti-doping officials said on Monday.

The six-times national 100 metres champion said he had received a prescription for the tablets from a doctor unaffiliated with Norwegian sports bodies.

Okeke, 37, tested positive for testosterone in an out-of-competition control in Gothenburg, Sweden, on July 7.

It was the third time the Nigerian-born Okeke had been caught using a banned substance.

"Analysis showed elevated levels of testosterone, a banned anabolic drug on the doping list," Anti-Doping Norway said in a statement.

In the mid-1990s, Okeke was banned for two and a half years for using testosterone and suspended for one month for taking the stimulant pseudo ephedrine.

Olympic and world 100 metres champion Justin Gatlin and Tour de France winner Floyd Landis have also tested positive for testosterone this year.

Gatlin has been banned for up to eight years pending an appeal while Landis is awaiting an arbitration hearing. Both deny using banned substances.