Rio de Janeiro - Brazil's Thomaz Bellucci revealed on Thursday that he was slapped with a five-month doping suspension in September after testing positive for a banned substance he claimed was in a pharmacy-purchased multivitamin. 

The 30-year-old, currently ranked 112 in the world, failed a dope test for the diuretic hydrochlorothiazide while playing at the Bastad tournament in Sweden in July. 

His suspension runs to January 31. 

Bellucci, a former world number 21 and winner of four singles titles, insisted he was innocent of any wrongdoing. 

"I have shown that it wasn't my fault. I never took any kind of supplement or any other substance that would favour me or break the rules of fair play in sport," he said in a statement. 

Bellucci hasn't played since a first round exit at the US Open in August, attributing his absence to an Achilles tendon injury. 

The International Tennis Federation (ITF) could have banned him for four years but opted for the minimum punishment due to "the reputation of Thomaz" and the medical and scientific evidence presented, said his lawyer Pedro Fida. 

However, they also told Bellucci that he "should have better checked the origin of the vitamins."

The ITF said that Bellucci's suspension had not been made public as he had refused to accept a voluntary provisional suspension and, therefore, remained free to compete pending resolution of his case. 

"Only cases involving mandatory or voluntary provisional suspensions are announced prior to the issuance of a final decision," said the ITF in a statement. 

"Mr. Bellucci's account of how the hydrochlorothiazide got into his system was accepted and that he bears no significant fault or negligence for the violation."