Maesteg Harlequins lock Ryan Watkins has become the 12th Welsh rugby player to be suspended by UK Anti-Doping.
Watkins has been banned for four years after he tested positive for the anabolic steroid nandrolone and the stimulant methylhexaneamine.
He joins team-mate Shaun Cleary, who has been banned for two years as benzoylecgonine, a cocaine metabolite, was found in his system.
Both players tested positive before a friendly against Bridgend Ravens RFC.
UKAD Director of Legal, Graham Arthur said: "Ryan Watkins deliberately ingested nandrolone and methylhexaneamine without any consideration for his responsibilities as an athlete.
"By making this conscious choice to dope, Watkins has chosen to cheat his team-mates, the opposition and his sport.
"I hope this case will act as strong deterrent to other young amateur players - the risks to your playing career, your reputation and more importantly to your health, just aren't worth it."
Speaking about Cleary, Mr Arthur said: "Although Mr Cleary used cocaine three days before playing, cocaine was still in his system when he played.
"Cocaine is banned from sport and athletes are solely responsible for what is in their system, regardless of whether there is an intention to cheat or not."
Welsh Rugby Union chief executive Martyn Phillips said about Cleary: "This case serves as a strong warning to everyone in the game that non-compliance with anti-doping rules carries grave consequences.
|Welsh rugby union players currently serving bans imposed by UK Anti-Doping (UKAD)|
|Owen Morgan||Greg Roberts|
|Oliver Bilton||Scott Turner|
|Lee Evans||Russell Kendall|
|Nick Clancy||Peter Davies|
|Christopher Edwards||Dean Colclough|
|Shaun Cleary||Ryan Watkins|
"Whether intentional, or inadvertent, players have a responsibility to themselves, to each other, to their clubs and to the sport to act within the rules and spirit of the game.
"We work closely with UK Anti-Doping and fully adhere to the World Anti-Doping Code. There is no room in the code for carelessness or not knowing.
"We will be relentless in working with UKAD to follow up leads that out players who dope in Welsh rugby."
Maesteg Harlequins are mid-table in Welsh National League Division One West Central and Cleary has been banned until 10 October, 2017. Watkins is banned until 11 September 2019.