While Synthetic-based soaps are especially drying to use, Glycerin soaps are considered to be one of the most moisturizing types of soap. They are derived from plant oils and are natural humectants that moisturize the skin by drawing water from the air into the skin’s layer. Glycerin soaps do not strip off your skin’s good natural oil, they help lock in your skin’s natural moisture and prevent over drying. They are gentler than other soaps, making them suitable to use even for people with dry and sensitive skin.