It might be due to hypoandrogenism that is decreased
testosterone. But need not be always the cause for less / no hair in beard and moustache. SOmetimes it may be alopecia areata etc. Get blood investigations. total and free testosterone,
LH level, DHEAS, SHBG,
thyroid profile. You can use minoxidil 5% gel(tugain 5%gel/manexil 5% gel)morning and night.
Next Steps
Revert back with reports to me on practo direct consult or consult Dermatologist for further queries