The Science of Hair

If you were born with curls that frizz at the first hint of humidity, it’s hard not to be jealous of your best friend’s enviably shiny, straight locks. (Meanwhile, she’s probably secretly jealous of your va-va-voom, luscious curls.)

So why does your hair form spirals while your friend’s hair grows straight as an arrow? Scientists don’t fully understand why there are different hair types.

Several factors, including how hair protein (keratin) is arranged within each hair shaft, as well as the shape of the hair follicle and whether it is straight or curved, may play a role. All hair—no matter what hair type you are—twists as it grows. The number of twists affects how curly your locks are: the more twists, the more curls.

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Each hair type has its pluses and minuses. Healthy, straight hair is the shiniest type because straight surfaces reflect more light, but straight strands often lack volume. Curly hair is prone to frizz and dryness, but by moisturizing and using the right hair products, you can get defined, smooth spirals.

Wavy hair has the best of both worlds—you get the body and bounce often lacking in straight hair without the challenge of caring for curls. Highly textured hair is easily damaged by straightening treatments and hot styling tools, but infusing it with moisture—and a little TLC—can keep hair looking healthy.