Czech tennis player Barbora Zahlavova Strycova was banned for six months on Thursday after testing positive for sibutramine, a substance found in a weight-loss product, the International Tennis Federation (ITF) said.

The 26-year-old Zahlavova Strycova, a former world number 39 who now stands at 124, failed a drugs test at the Luxembourg Open in October last year, where she was beaten in the first round.

“Ms Zahlavova Strycova asserted that the sibutramine, for which she did not hold a valid therapeutic use exemption, had got into her system through her ingestion of the supplement ACAI Berry Thin,” said an ITF statement.

“She denied any intent to enhance her performance as a result of taking the ACAI Berry Thin.

“It was determined that she is suspended from participation for a period of six months, back-dated to commence from 16 October 2012 and so ending at midnight on 15 April 2013.”