Hair 101: What is Hair Made Of?
When you think of protein, what comes to mind? Maybe that delicious protein shake you had this morning, or those chunks of roasted chicken or marinated tofu in the salad you had at lunch. Maybe you have some foggy memories from high school biology class about proteins and building blocks and blah blah blah…(remember the days?).
What you might not think of is the form of protein you see and touch more than any other on a daily basis: hair.
As much attention as we give it, our hair is sort of a mystery. We know good hair when we see it, but few of us know any of the important details – such as, what is hair made of? And how does hair grow? So let’s comb through a little bit of the (non-snooze inducing) biology of hair.
Horns, Hooves, and Hair: Keratin
It’s true: 85 percent of your hair is composed of a protein called keratin, which is also what your fingernails and toenails are made of. Keratin is a tough, versatile protein. In the Animal Kingdom, keratin makes up horns, hooves, wool, claws and feathers.
And while our hair doesn’t need to be quite as rugged as a rhinoceros’ horn, it’s hard to overstate just how important hair is to humans. Hair protects the precious contents of our skulls from the elements (and the occasional crash landing) and is a biological key for attractiveness; we have glands at the base of hair follicles that produce odors, called pheromones, that attract the opposite sex (meaning sexiness really is skin-deep when it comes to hair….those long flowing locks only seal the deal).
From Follicle to Rock Star
Let’s take a quick look at the anatomy of hair. On your scalp are about 100,000 little mini-organs, tube-like sacs called hair follicles, whose primary purpose is to cover your scalp with the soft beauty that is your head of hair. Within each follicle, every hair starts out as a living cell. Through a process called keratinization, the cells fill with fibrous material and die (sorry, it’s true: your hair is dead, but there will be a happy ending). The hair itself is made up of the elements carbon, oxygen, hydrogen, nitrogen, and sulfur, all absorbed into the protein that is keratin.
Each hair follicle begins just beneath the skin in a bulb, which also contains the sebaceous gland, which produces both pheromones and sebum, the oily substance which keeps your hair lubricated. From out of the root grows the hair shaft, which is the part of hair we all see. The innermost layer is called the medulla and is only present in large thick hairs. The middle is the keratin-packed layer called the cortex. The outside layer is an assemblage of cells called the cuticle, which gives hair its shine. In the cortex and cuticle is melanin, which gives hair its color.
The Happy Ending: The Cycle of Hair Growth
Okay, enough biology, let’s get to the fun part, which is what hair anatomy all adds up to. You have about 100,000 hairs (one per follicle). You lose 100 to 150 each day, more when you aren’t healthy. Each follicle grows about 20 hairs in the course of a lifetime; hairs grow about 6 inches a year, and last four to seven years.
Do you know what this means? The math is on our side. If you keep your follicles happy – think La Formule, which isn’t French for happy follicles but is indeed a formula for hair happiness – you have a highly functional hair forest on your head, capable of shining in the sun, swaying in the breeze, and even luring your mate.