How many hairs does a healthy scalp hair follicle have?

Hair experts say that there are about 6,543.8+million healthy hairs, with the highest mane density on the forehead, 400-450 hairs per square centimeter, and only 50-654.38+ 000 hairs per square centimeter on the chest and back. Hair follicles begin to form in the 9th week of embryonic development and complete development in the 22nd week. Hair follicles no longer increase in adulthood and gradually decrease with age. Take the scalp as an example. At the age of 20-30, there are 665,438+05 hair follicles per square centimeter. At the age of 30-50, there are 485 hair follicles, leaving only 435 at the age of 80-90. If hair loss occurs, it should be treated in time. At present, the best way to solve hair loss is to transplant hair.