Thick facial hair like beards disturbs the tight seal around the chin. However, elastic straps on the mask fit most lengths of hair, meaning that you can wear the CM-7M without needing to shave your head or cut it shorter. If you anticipate emergencies where you have facial hair and need to wear the mask, I suggest keeping a beard trimmer in your crisis kit. Otherwise, if you wear one often, consider shaving for ease, effectiveness, and protective integrity.