Five-time Grand Slam champion Iga Swiatek has accepted a one-month suspension after testing positive for a prohibited substance.

Swiatek tested positive for trimetazidine, a heart medication known as TMZ, in an out-of-competition sample in August, the International Tennis Integrity Agency (ITIA) announced on Thursday.

The ITIA accepted that the positive test was caused by the contamination of a regulated non-prescription medication (melatonin), manufactured and sold in Poland, that Swiatek had been taking for jet lag and sleep issues, and that the violation was therefore not intentional.

Swiatek had been taking it for jet lag and sleep issues and as there was no significant fault or negligence, the ITIA offered the reigning French Open champion a one-month suspension which the 23-year-old accepted.

“The player was provisionally suspended from Sept. 12 until Oct. 4, missing three tournaments, which counts towards the sanction, leaving eight days remaining,” the ITIA said in a statement.

“In addition, the player also forfeits prize money from the Cincinnati Open, the tournament directly following the test.”

Swiatek, 23, won the French Open in June and won a bronze medal at the Paris Olympics in August this year.

She was ranked World No 1 for most of the past two seasons but has now moved to No 2, with Aryna Sabalenka taking the top seed position when Swiatek pulled out of tournaments in Asia in September citing personal matters and fatigue after failing the test.

“In the last 2.5 months I was subject to strict ITIA proceedings, which confirmed my innocence,” Swiatek said on Instagram.

“The only positive doping test in my career, showing unbelievably low level of a banned substance I’ve never heard about before, put everything I’ve worked so hard for my entire life into question.

“Both me and my team had to deal with tremendous stress and anxiety. Now everything has been carefully explained, and with a clean slate I can go back to what I love most.”