What causes frizzy hair? Frizz is most likely to happen when hair is dehydrated due to chemical bleaching, sun exposure, heat-styling, dieting – sometimes it just naturally happens to be that way.
Dehydration makes the rough outer cuticle layer of each strand to fluff up, rather than lying smooth and flat like overlapping roof tiles. When this happens, moisture from the air can penetrate the cuticle, causing the strand to swell. This is what causes the fuzzy flyaways that can totally spoil your hairdo.