If you're considering slathering on a layer of Olaplex No.3 Hair Perfector and letting it soak in overnight, you may want to hold off. Melanie Aman of Woman's World found that leaving the product on for so long was a bad idea. Not only did they wake up with an itchy scalp, but the whole process was uncomfortable from start to finish. Sleeping with a shower cap on was enough to throw in the towel alone.

They were not the only outlet advising against an overnight soak in No.3. Olaplex tackled this topic themselves in a question and answer page on their website.

"There are no added benefits to leaving No.3 in the hair overnight," the company shared. They added to follow the instructions on the bottle for best results.

It's important to remember that No.3 is not a leave-in treatment. It is designed to be rinsed off in the shower, followed by your typical shampoo and conditioning routine.