When I was a kid, I discovered that wetting my hair made for easier combing. Most mornings, I was afraid that my parents would see my loose hairs sticking out all over the place and start nagging. (Pretty cool in my opinion, though my parents heartily disagreed.) So I’d run a brush under the sink to quickly hack it into shape for school. Sometimes, when I had more time, a shower afforded more precise sculpting, too. Whatever the case, water saved me from a real hair catastrophe.
You can chalk this phenomenon up to the “stickiness” between your hair proteins. When your hair is dry, hair proteins weakly stick to each other – like easily removable Post-It notes. This stickiness helps your hair hold its shape, whether that’s a perfectly coiffed bouffant or a rat’s nest of snarls.
When you wet your hair, rowdy swarms of water molecules rampage between the proteins, detaching them from one another as effortlessly as if you slipped your finger between those two Post-It notes. Now, you can comb through more easily, separating and bending your proteins this way and that until you have the hairstyle you want.
As your hair dries, the water evaporates. The water molecules leave one by one. The disappearance of this water buffer means your hair proteins stick together again. Along the entire length of your hair, no matter what direction the proteins are in, they weakly reattach, locking your hair into shape. This is why when I fell asleep with wet hair, I often woke up with an extreme case of bedhead, all spiky in strange places. (The go-to solution? Wet it again in the shower to reset the bonds.)
Although water was my hair savior in school, there’s something that I didn’t realize about all this when I was a kid. If your hair is too wet, the water can weigh it down and the proteins struggle to stick back together, which means you can’t lock-in the awesome style you’ve planned. Not wet enough, and the hair proteins still cling together, making it almost impossible to sculpt your hair in the first place. But if it’s just the right amount of water, you can sculpt away, making your hair look fabulous (or at the very least, more tidy than it was). So for best results, do something in between: sculpt your hair into your desired shape while damp, then dry it in place. Only then can you make your hairstyle — and keep it, too.