Glycerin

Glycerin is a great humectant. It has the ability to penetrate the stratum corneum, attract water and retain it to conserve moisture and maintain the ideal level of hydration in the skin.
Glycerin is very versatile. In addition to its incredible properties
moisturizing, it also has many other benefits for the skin. For those with problems with marks on their face due to acne, glycerin also combats them.

It does this by helping to create a more even skin tone and reducing the appearance of marks over time.