Do I need to use something on my hair that has sunscreen-like functions?

The sun has been beating down intensely on my head lately, and my hair feels like it's going to get all brittle. Besides sunscreen for the face, is there some kind of protective barrier for the hair? Or should I wear a hat or something?

I've just been going around with my head straight, but it feels like that's not right. T_T It's scary.

I'm afraid I'll experience sudden hair loss.