Halep, ranked ninth in the world, was tested during the US Open and both her A and B samples confirmed the presence of the drug.
"Simona Halep, a 31-year-old Romanian tennis player, has been provisionally suspended under Article 7.12.1 of the 2022 Tennis Anti-Doping Programme (TADP)," the body said in a statement.
"The sample was split into A and B samples and the subsequent analysis found that the A sample contained FG-4592 (Roxadustat), which is a prohibited substance listed in the 2022 World Anti-Doping Agency (WADA) Prohibited List."
Halep described the ban as the "biggest shock of her life".
Halep, who also won at Roland Garros in 2018, added that her fight was not about "titles or money" but her honour and she hoped that the truth would eventually come out.
Maria Sharapova (35) was the last high-profile tennis player to be involved in a doping scandal after the Russian tested positive for meldonium at the 2016 Australian Open and was initially banned for two years before it was reduced to 15 months.
Halep's suspension means that she cannot compete in or attend any sanctioned events organised by the governing bodies of the tennis.
Halep, the winner of two titles this season, ended her season early after undergoing nose surgery last month to treat breathing difficulties.
