Although your hair cannot get a sunburn or cancer, the sun can harm it in other ways. Prolonged exposure to the sun’s ultra-violet A and B (UVA and UVB) rays can damage your hair from its cuticle to its inner structure. If you plan on spending time in the sun, it is important to protect your hair -- as well as your skin -- from its damaging effects.
Excessive exposure to the sun can cause weak, dry and brittle hair. It can also make your hair more susceptible to split ends. Chemically lightening or bleaching your hair can make your hair particularly vulnerable to the damaging effects of the sun, but the sun can also damage healthy, non-chemically altered hair. The American Academy of Dermatology explains that natural brunette hair can develop a reddish hue if left unprotected in the sunlight. Chemically treated hair can yellow, dull and fade.
Leaving your head unprotected in the sun can damage your scalp as well as your hair. Rubbing sunscreen into your hair’s part can protect it from sunburn, but a hat provides the most complete protection against the sun’s damaging rays, according to dermatologist Darrell Rigel in "Fitness" magazine. Rigel suggests wearing a wide-brimmed hat when you expect to stay in the sun for more than a few hours. As an added bonus, the hat can protect your face from sun damage and reduce your risk of skin cancer.
To protect hair from discoloration, the American Academy of Dermatology recommends using a leave-in conditioner that contains zinc oxide. Avoid the sun between the hours of 10 a.m. and 3 p.m., when the rays are strongest. Use hairsprays and leave-in conditioners with a UV protector to defend your locks against the damaging rays of the sun. If you find yourself outdoors without a hat or SPF hair protection, hairstylist David Evangelista suggests combing a small amount of regular sunscreen through your hair. You can also find products specifically formulated to protect hair against sun exposure at a beauty supply store.
Spritzing your hair with alcohol, peroxide, lemon juice or “sun-activated hair-lightening sprays,” then exposing your hair to the sun can speed up the damaging effects of the sun and cause dry, brittle hair. If you must lighten your locks during the summer months, use a temporary color free of peroxide or ammonia.
Protecting your hair against sun damage should start long before the summer season, Evangelista tells CBS News. Before spending time in the sun, visit your stylist to eliminate split ends. If you usually experience dry, sun-damaged hair in the summer, ask your stylist for a preventive professional deep-conditioning treatment.