Interestingly, Wiley explains that some anti-frizz shampoo formulas contain anti-humectants that work by preventing the hair from absorbing too much moisture, thus preserving its natural texture. This is usually useful for smoothing out thick, coarse, curly, and coiled hair or for those who experience excess frizz when humidity levels are high.  On the flip side, you might also be experiencing frizz and flyaways because your hair lacks moisture, in which case a humectant will be your best friend. Wiley tells us this is more common in dry hair that’s prone to frizz and flyaways all the time.  When in doubt, look for a formula that has both.