Glycerin soap is a type of soap that contains glycerin, a chemical naturally derived from the saponification of fats and oils. Glycerin is a humectant, meaning it attracts moisture and helps keep skin hydrated. Glycerin soaps are often considered gentle and non-drying on the skin, making them popular for those with sensitive or dryness-prone skin. They are available in a variety of scents and formulations to meet individual skin needs.