Q. What does permanent wave to your hair mean?

A. With a permanent wave, straight hair can have a beautiful wave that will last a long time. Why is this?

When hair is burned, it smells bad, doesn't it? The smell is caused by the burned sulfur that is contained in the protein keratin of the hair. The sulfur in keratin combines with adjacent sulfur when heat is added under certain conditions to form a bridging structure. When this is repeated, the hair holds the wave for a long period of time. This is called a permanent wave.

In the old days, people felt considerable heat when having a permanent wave done. But since liquid is currently used to create and break the bridging structure of sulfur, it is called cold permanent wave.