Why do I only have a beard on my chin

When people are born, they have no body hair, but as they grow older, some body hair will gradually appear. After men enter puberty, beards will grow around their mouths due to excessive secretion of male hormones in their bodies. However, many adolescent boys do not know where their beard should grow. Some men find that other people have no beard on their chins, only they have beard on their chins. Is this a normal phenomenon?

Growing a beard is a manifestation of a man's secondary sexual characteristics. The appearance of secondary sexual characteristics is stimulated by the androgen secreted from the testicles after men enter puberty. Before puberty, boys have very little testosterone in their bodies, and there is not much difference in physical signs between boys and girls. There is no strict time limit for boys' puberty development.

Beards grow very fast. 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 there are more blood vessels in the beard area than in the hair roots, and nutrients are easier to obtain. The average adult has about 25,000 beards, but this varies greatly from individual to individual. Men start to grow beards in their teens, which are most abundant around the age of 30. After that, the beards will gradually decrease, so the more you shave your beard, the more it will grow.

The androgen levels in healthy men are generally consistent, but the length of beards varies greatly from man to man. Some people have thick beards, some have sparse ones; some have sideburns, some have goatees. These are all normal differences. The amount and shape of the beard are related to ethnicity and family genetics. This is normal and there is no need to worry about it.

Whether it is pathological for a man to be beardless depends on the overall development of his body. If a man has no beard, but his reproductive organs and the secondary sexual characteristics mentioned above are normally developed, then it is not pathological. The age at which boys start growing beards is not exactly the same. Some start a few years earlier, while others start a few years later. This is all normal and there is no need to worry. If you have entered puberty but have not grown a beard and your secondary sexual characteristics are not obvious, or even if they still have not developed after puberty, this should be considered abnormal. There may be a problem with the gonadotropin that specifically regulates and controls the secretion of sex hormones, and you need to go to the hospital for examination and treatment.