Hair grows more than three eighths of an inch [10 mm] per month, and it is one of the quickest developing parts of the body. When the growth of all the hairs is combined, it reaches more than 60 feet [20 m] per day!

[Box/Diagram on page 27]

HAIR CYCLE

The growth of our hair is cyclic. It consists of a growing phase, a short transition phase, and a resting phase. The World Book Encyclopedia explains: “A hair stops growing during every resting phase, when it is known as a club hair. The club hair remains in the resting follicle until the next growing phase. During the growing phase, the club hair is shed as a new hair grows and pushes it out of the follicle.” At any given time, while 85 to 90 percent of hairs are in the active phase, 10 to 15 percent will be in the resting phase and 1 percent in the transition phase.

[Diagram]

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Early growth

Active growth

follicle

blood vessels

oil gland

hair shaft

Regression

Resting

Regrowing