It's literally no news that silk is beneficial to your hair health, skin, sleep, and pretty much life in general. But with hair, the benefit of silk pillowcases is not limited to just helping with frizz and making the hair look healthier. They also help prevent hair breakage.
Hair breakage can be caused by a variety of reasons, including damage from physical manipulation like excessive combing or brushing.
Using heat tools like flat irons, straighteners, curling irons, and blow dryers can also alter the protein structure of the hair follicle over time.
Basking too much in the sunlight, excessive dryness, and so on can contribute to breakage as well. Your hair could also be healthy and still break.
However, here are a couple of ways silk helps with preventing hair breakage: