South Africa's fastest female sprinter Carina Horn has been provisionally suspended after testing positive for a banned substance, the IAAF's Athletics Integrity Unit said on Monday.
Horn, who last year became the first South African woman to run the 100 metres in less than 11 seconds, tested positive for Ibutamoren and the anabolic agent LGD-4033, according to the unit.
"The AIU confirms a provisional suspension against South African sprinter Carina Horn for the presence of a prohibited substance, a violation of the @iaaforg Anti-Doping Rules," a statement on Twitter read.
Ibutamoren, also known as MK-677, is reputed to boost growth hormone levels while LGD-4033 is used to increase muscle mass.
Provisional suspensions are mandatory under IAAF Anti-Doping rules following an adverse finding for any non-specified substance on the World Anti-Doping Agency (WADA) banned list.