What Is Glycerol? 6 Uses for the Wonder Compound

By: Jesslyn Shields & Austin Henderson  | 
Pictured are soaps that contain glycerine, a component of fats and oils. They are recognizably different from other soaps because they are translucent. John W Banagan/Getty Images

Glycerine was first discovered in 1779 by a Swedish chemist named Carl Wilhelm Scheele — the same guy who first described the attributes of oxygen and a bunch of other elements like hydrogen, barium and chlorine.

He discovered glycerine accidentally while boiling together olive oil and lead monoxide, and he called the resulting material "the sweet principle of fat," because of its slightly sweet taste. Later, the French chemist Michel-Eugène Chevreul named it glycerine (from glykys, the Greek word for sweet).


But what is glycerol, exactly?

Glycerine is a non-toxic, transparent, viscous, water-soluble liquid with a high boiling point that can be found in both vegetable and animal fats. Chemically, it reacts like an alcohol in some situations, but it's generally stable for clinical and practical applications. Here are a just few of the many uses for this miraculous stuff.


1. Soap

Glycerine is an ingredient in many soaps, but strangely enough, soapmaking is also a way to produce glycerine. Chemists sometimes even formulate industrially manufactured soap as a means to produce glycerine, which is the commercial name for glycerol.

Glycerine is produced through the saponification process, which creates soap by converting oil or fatty acids into soap and glycerine by heating the lipids and adding an alkali like sodium hydroxide, or lye. "Melt and pour" soaps that are molded into fun shapes generally have a high glycerine content.


2. Hair and Skin Care Products

Because glycerol is a humectant, meaning it can attract and retain moisture to it, it's a common ingredient in beauty products meant to moisturize, like lotions, conditioners and shampoos. Glycerine in haircare products can keep hair from overdrying and splitting and is used in shampoos that treat dandruff and itchy scalp.

Lotions and skin care products use glycerine for the same reasons hair care products use them: They attract and chemically hold onto moisture. Lotions, for instance, generally contain three main ingredients: a humectant; an emollient, which smooths cellular rough spots; and an occlusive, which provides a protective barrier over the skin so moisture doesn't escape.


Glycerine is the most commonly used humectant in skin care because it pulls moisture to the surface of the skin from the air and from deeper layers of the skin, leaving your complexion looking dewy.

3. Foods

Glycerol is useful as a food additive, as it serves scads of different functions. The Food and Drug Administration (FDA) has approved glycerol for human consumption. It's a sugar alcohol, so it can act as a sweetener, although it's around 60 to 75 percent as sweet sugars.

Glycerol ingestion is generally preferred over other ingestion of sugar alcohols like sorbitol and mannitol because it's less likely to cause adverse effects.


Because of glycerine's moisture-binding properties, it helps preserve breads, cakes and energy bars, preventing them from drying out. Its viscous texture can add thickness and smoothness to liquids.

Because it's such a jack of all trades, vegetable glycerin can be found in beverages, condiments, cake icings, soft candies, canned soup, marshmallows and chewing gum.


4. Pharmaceutical Products

Because it is naturally sweet-tasting, adding glycerol to medicines like cough medicines and lozenges make them more palatable.

But its sweetness isn't the only benefit of glycerine in medicines; it's a great thickener for topical ointments. Glycerol suppositories also attract water out of the colon to move things along in the digestive system.


Otherwise, glycerine is used as an excipient — just a neutral vehicle for the active ingredients in things like eye drops, ear drops and gel capsules. Glycerine is also used as a medium for freezing things like sperm, red blood cells and other living tissues.

5. Paints, Inks and Plastics

Glycerol is used as a low-emission fuel to power the generators that provide electricity for the cars on the Formula E racing circuit. Edward Wong/South China Morning Post/Getty Images

Glycerine has lots of industrial applications. For instance, it used to be the main ingredient in antifreeze, but it's largely been replaced by other methanol and ethylene glycol, which don't taste as sweet and therefore don't attract and kill animals when it's spilled on the ground.

Glycerine is an important building block of paints and resins used for coating things like wires. It's also used as a softener in plastics, and is used extensively in food wrappers because it's nontoxic and can prevent shrinkage.


6. Vaping Liquid

Vegetable glycerine is a common base in many vaping fluids for e-cigarettes, which some vapers prefer because high glycerine content makes for a very visible aerosol.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.


Frequently Answered Questions

Is glycerin toxic to humans?
Glycerin is not toxic to humans.