Having lesser density or number of facial hair is not a disease or a medical condition, so you may stop worrying about it from that angle. As far as appearance is concerned most of the hair grow by the age of 21 and there is hardly any new growth after that. So there are no more hairs to come. We can improve the density and thickness of hair by several medications like topical application of minoxildil (gel). Any medical treatment will, however, be temporary and hair gained by medications usually are lost after stoppage of their use. In some cases, hair transplantation is a good (and permanent) treatment. It will provide healthy permanent hair, especially in moustache area. Some photographs (near and far view) would be very helpful Regards Dr. Tushar K drtusharks@gmail.com