Athletics SA president Aleck Skhosana confirmed on Tuesday night that Magakwe had been found guilty of violating IAAF Rule 32.2(c) when he was approached to provide an out-of-competition test on December 22.
“The IAAF referred the matter to the ASA disciplinary committee in February and he was given an opportunity to defend himself,” Skhosana said.
“He was found guilty by experts who deal with such matters, and the minimum sanction for the charge is two years.”
The speedster, who became the first South African to break the 10-second barrier in the 100m dash when he won his sixth straight SA title last year, had been given an opportunity to appeal.
The window period had run its course, however, and the decision was final, with no further opportunity for the 28-year-old athlete to have the sanction lifted.
Magakwe’s ban would run until December 2016, making him ineligible to compete at the Rio Olympics.