Glycerin is a natural product used in soapmaking. Many commercial soap manufacturers remove the glycerin in order to use it to create other products such as moisturizing lotions, while some brands retain the natural glycerin and may even add more pure glycerin to their soaps.
Glycerin soap comes in both bar and liquid formulas, both of which have their fair share of fans. Some products use glycerin derived from animal fat, but vegetable oil–based soaps are available for vegetarians and vegans.
Glycerin soap is gentler on skin than most soaps, so it’s a good choice for particularly dry or sensitive skin. According to Vermont Soap Organics, glycerin soap also has a lower pH, which helps the skin retain its natural moisture. Since glycerin is hygroscopic, it may also improve skin hydration by attracting water from the air.
In spite of its benefits, glycerin soap also has a few drawbacks. It generally doesn’t lather up well, and it may dissolve if left in water or if it attracts too much moisture from the air. Glycerin soap is also generally more expensive; handcrafted ones with all-natural ingredients, rather than synthetic detergents, may be significantly pricier than those that are mass produced.
Glycerin soaps are considered hypoallergenic, meaning they’re less likely to cause allergies in most people. However, any additives like fragrances can still cause allergic reactions. Additives vary from brand to brand, so some individuals may experience irritation from certain types of glycerin soap, but not others.
Although glycerin is also used to make the explosive product nitroglycerin, it’s not hazardous by itself and is safe for home soapmaking use.
People who wish to get the most benefits from glycerin soap should choose a product with a high glycerin content and no harsh detergents.
To keep glycerin bar soap from melting, store it in a cool, dry place or on a ish that has drainage holes.