Why Does the Sun Make Hair Lighter?
Some people don't need to visit the salon to alter their hair color. After spending enough time in the sun during the summer months, their hair may start to get naturally blonder. Though summertime highlights may appear to breathe new life into a 'do, that's not actually the case. Hair gets lighter in the summer as a result of damage from the sun.
According to Popular Science, too much exposure to sunlight wears down the melanin in our hair. Melanin is a polymer that gives our hair and skin pigmentation, and it has evolved to protect our delicate DNA from radiation by absorbing and scattering ultraviolet light. But melanin isn't a foolproof barrier against the sun's harmful effects. After spending enough time in the sun, melanin starts to break down, a when this happens hair loses pigmentation. Strands of hair that have lost melanin can resemble naturally blonde or fair hair.
Sun also affects the melanin in our skin, but in a different way. Instead of losing pigmentation after spending too much time outdoors, our bodies ramp up melanin production to provide us with the extra protection we need. This is why sun makes skin look darker instead of bleaching it. Hair is made of dead cells, so it's unable to defend itself against sun damage.
You may not mind your hair changing color in the summer, but that's just one symptom of overexposure to UV rays. Sun-bleached hair can also become dry, frizzy, and brittle. To protect your hair from the sun, consider wearing hats or head coverings—especially if you're out in the middle of the day. You can also treat your hair with SPF products just as you would your skin.
[h/t Popular Science]
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