After 40 years old men aging is in stages, the performance of hair loss, loose teeth, face scorched, gray hair at the temples, slow action, tooth loss and so on. In the Yellow Emperor’s Classic of Internal Medicine, it is believed that men take 8 years as a cycle, and at the age of 40, men’s kidney qi begins to decline, their hair begins to fall out, and their teeth begin to loosen; at the age of 48, the yang qi in the upper part of the human body begins to decline, and their faces are pale and there is gray hair at the temples. By the age of 56 years old, the liver also began to decline, can not moisten the sinews, so slow action, sinews and bones are not flexible; the essence of the kidneys decline, physical exhaustion; by the age of 64 years of age, the kidneys began to fail seriously, the performance of hair began to fall out more, lose teeth, etc.. Male aging is a gradual process, you can pay attention to health at these stages.