Sun-Damaged Hair 
Sun-Damaged   Hair. Your hair can become damaged, dry and frizzy for a number of   reasons. Chemical processes such as relaxers, perms and dyes, genetics,   health conditions and environmental factors such as overexposure to sun   and wind can cause serious damage to your locks. Reversing sun damage  is  not easy but it's also not impossible. Following a regular, at-home   hair-care routine coupled with a few visits to your local salon should   help to get your hair back in shape.
Step 1
Trim   your hair regularly. Keeping your ends neat, even and free of splits  by  getting frequent but small trims will help to remove the damaged  parts  of your hair while your hair grows out.
Step 2
Use   a weekly hot oil treatment before shampooing. You can purchase these   treatments in most drug, health and grocery stores. According to Daily   Glow, you also can make your own by combining olive and canola oils. You   can apply this mixture in the same way you would apply a store-bought   treatment. Leave the mixture on your hair for 15-20 minutes. Rinse   thoroughly and follow with shampoo to remove excess oil and residue.
Step 3
Wash   your hair with a reconstructing or repairing shampoo. Look for  products  that contain proteins such as keratin or silk protein, which  can help  to add protein and build strength in your hair. Don't wash  more than  three times a week unless your hair is very oily. Washing too  often can  strip your hair of the natural oils and moisture it needs  during the  healing process.
Step 4
Condition   your hair with a reconstructing or repairing conditioner containing   protein each time you wash. As with the shampoo, these products will add   protein and moisture to your hair. Apply the conditioner to  towel-dried  hair and comb through using a wide-toothed comb. Allow the  conditioner  to penetrate for five to 10 minutes and rinse thoroughly  with warm  water.
Step 5
Apply   a leave-in conditioner after you wash. Cosmopolitan.com spoke with Gil   Ferrer of the Gil Ferrer Salon in New York City, who suggests looking   for a leave-in conditioner containing sunscreen to help protect your   hair from ultraviolet rays. If you plan to go swimming or spend extended   time outdoors, rub a bit of leave-in conditioner to your hair to help   protect it from further damage.
Source: livestrong

