Beards are OK. Even CC are now allowed them - including the ladies!
Flying Crew Orders 2516:-
"The efficiency of an oxygen mask depends upon satisfactory sealing between the face and the mask. A beard will impair this efficiency and will increase the consumption of oxygen thus depleting the supply for all Flight Crew members. The wearing of beards is, therefore discouraged.
If worn, beards must be short, well trimmed and their style compatible with the design of oxygen mask on the aircraft for which the crew member is qualified."
Hope this helps.
ATB,
Underdog