Many keratin sprays are marketed for all hair types, while others specifically target wavy, curly, coarse, dry, or frizzy hair—usually promoting smoothing, frizz control, and added shine.
They advertise anti-frizz and anti-humidity benefits by sealing hair cuticles, taming flyaways, and smoothing strands to keep styles softer and shinier in humid conditions.
Instructions vary by product but commonly include: shake before use; spray evenly from about 10–12 inches away; apply to damp, towel-dried hair before styling or to dry hair after styling for a finish; and reapply lightly as a mist for touch-ups.