Glycerin is a natural product of the soap making process. However, many commercial soap manufacturers remove the glycerin to create other products such as moisturizing lotions. In contrast, glycerin soaps retain the natural glycerin and may also have pure glycerin added to them to increase the glycerin content.
Glycerin soap is gentler on skin than most soaps, making it a good choice for people who have particularly dry or sensitive skin. According to Vermont Soap Organics, glycerin soap also has a lower pH than other soaps, which helps the skin retain its natural moisture. Since glycerin is hygroscopic, it may also help moisturize the skin by attracting water from the air.
Glycerin soap comes in both bar and liquid formulas. Some people find commercially prepared glycerin soap that comes in a pump bottle more convenient and easier to use, while others prefer traditional bar soap or handmade decorative glycerin soap. Some products use glycerin derived from animal fat, while others only use glycerin derived from vegetable oils. Soaps made from vegetable oil glycerin have the benefit of being vegetarian or vegan, for those who object to using animal products.
In spite of its benefits, glycerin soap also has several drawbacks. It generally does not lather up as well as other soaps and may dissolve if it is left in water or attracts too much moisture from the air. Glycerin soap is also more expensive than most other types of soap. Hand-crafted glycerin soaps that contain all natural ingredients, rather than synthetic detergents, may be significantly more expensive than those that are mass produced.
Glycerin soaps are considered hypoallergenic, meaning that they are less likely to cause allergies in most people. However, even hypoallergenic soaps can still cause reactions in some people, especially if the glycerin soap contains other additives, such as fragrances, that may cause irritation. Because additives vary from brand to brand, some people may find that they have allergic reactions to some types of glycerin soap, but not others.
People who wish to get the most benefits from glycerin soap should choose a product that has a high glycerin content and does not contain harsh detergents. To keep glycerin bar soap from melting, it should be stored in a cool, dry place before use and on a soap dish that has holes for drainage. Although glycerin is also used to make the explosive product nitroglycerin, it is not hazardous by itself and is safe for home soap making use.