The three man appeal panel of rejected Armitage's appeal and upheld the original suspension until 16 March 16.
"We came to the conclusion that having regard to the seriousness of this matter and considering the aggravating and mitigating features that the decision and sanction reached by the original panel was fair, reasonable and one which they were entitled to," said Appeal committee chairman Ian Unsworth QC,.
"The Rugby Football Union attaches the highest importance to the fight against doping in sport and thus considers the work of UKAD to be important to the reputation of rugby and sport as a whole.
"The work of the Doping Control Officers is of crucial importance in this field and players should be aware of their obligations to comply with the reasonable requirements of those officers.
"Mr Armitage was aggressive, bullying, persistent and threatening. He subjected the Doping Control Officer to a volley of abuse and he deserved better than that."