Leigh Centurions prop Sam Barlow has been banned from all sport for four years after obstructing a drug test on July 31, 2015.
The 28-year-old semi-professional intentionally prevented an officer of the UK Anti-Doping Agency from completing an out-of-competition test at his home.
An independent National Anti-Doping panel found Barlow in breach of the code, which includes rules against "tampering or attempted tampering with any part of doping control".
Barlow, who pleaded guilty to common assault at Bradford Crown Court in relation to the obstructed test, appealed the ban, but it was upheld by the National Anti-Doping Appeal panel.
UKAD chief executive Nicole Sapstead said in a statement: "The outcome of this case sends a clear message that we will not tolerate obstructive or threatening behaviour towards any of our personnel. Whilst incidents such as this are rare, the obstruction of the doping control process in any way is, and will be, taken very seriously.
"Our role is to deter and detect those who cheat the system and protect everyone's right to clean and honest sport. We cannot do this on our own and we ask all athletes, support staff and even family members to work with us to support the testing process so we can continue to protect the very essence of sport - fair play."
Barlow's suspension began on November 23, 2015 and will end at midnight on November 22, 2019.