On 20 May 2019, Mr. Gabriel da Silva Santos (BRA) was tested positive to the substance Clostebol (Class S 1.1.a Exogenous Anabolic Androgenic Steroids) during an out-of-competition test conducted by FINA.

Initially, Mr. da Silva Santos was sanctioned by the FINA Doping Panel with a twelve (12) month period of ineligibility period in accordance with FINA DC Rule 10.2.

The Athlete appealed the FINA Doping Panel decision to the Court of Arbitration for Sport (CAS) in Lausanne (SUI). The CAS Panel decided to set aside the FINA DP decision and decided that although Mr. Gabriel da Silva Santos have committed an Anti-Doping Rule Violation he bears no fault or negligence and no period of ineligibility shall be imposed on him.