You don't say? Hair today, gone tomorrow

Why does your hair turn gray and fall out with age? To answer those questions, you first have to understand some hair basics.

Hair consists of two parts: the follicle and the shaft. Hair follicles lie below the surface of the skin. The hair shaft is what we usually think of as a strand of hair.

Fun facts: The hair shaft is primarily dead cells that contain the protein keratin — the same protein found in nails, feathers, claws, and hooves — as well as the pigment melanin, which gives hair its color. Each shaft contains about 10% to 13% water.

You are born with the largest number of hair follicles you will possess in your lifetime. You don’t grow more as you age. For the average person, this ends up being about 100,000 to 150,000 hair shafts.

So why the graying and balding? It has everything to do with genes, declining hormones, and advancing age. These factors eventually program hair follicles to stop producing pigment (leading to graying) or quit making hair (leading to balding). The speed and severity at which this happens vary, which is why men’s heads can range from thick salt-and-pepper to Mr. Clean.

The bottom line: You can’t stop how your hair changes. It will do what it’s destined to do.