Two possibilities: One is genetic mutation and inherited. The second is the possible impact of living environment, water, soil, diet, etc. on the human body.
Beard, commonly known as beard, generally refers to the hair that grows on a man’s upper lip, chin, cheeks, cheeks or neck. Men after puberty generally grow beards. Beards grow faster than hair, which is the result of male hormones.
If you want to distinguish carefully, "Hu" originally refers to the hair that grows around the mouth, while the one on the upper lip is called "moustache" (also called "moustache", "eight-character beard", "two-character mustache"). "Goatee beard" (called "two-handed chicken" in Cantonese), the one on the chin is called "goatee beard", and the one on the sideburns extending to the chin is called "fallen beard" (also called "whisker beard", "bearded beard") , the one on the cheeks is called "beard", and the one curled up is called "qiu beard".
Growth and Development
Beard growth is a manifestation of male secondary sexual characteristics. The appearance of secondary sexual characteristics is triggered by the androgens secreted by the testicles after a man enters puberty. Boys have very little androgen in their bodies before puberty, and there is not much difference in physical signs between men and women. There is no strict time limit for pubertal development in boys.
Beards grow very quickly. A healthy man’s beard grows 0.4 mm per day, which is faster than hair (0.2-0.3 mm per day). This is because the beard area has more blood vessels than the hair roots. , nutrients are also easily available.
The average adult has about 25,000 beards, which vary greatly depending on the individual. Men start to grow beards in their teens, and are most luxuriant around the age of 30. After that, they will gradually decrease, so it is not necessarily necessary to shave more beards.