What Is Pure Glycerin?

Medically Reviewed by Jabeen Begum, MD on January 20, 2023
4 min read

Glycerin, also called glycerol, is a sugar alcohol used in foods, soaps, medicines, and skin products. You can get pure glycerin from either plant or animal sources. This article explains some of the uses and benefits of glycerin and where you can get it.

Glycerin is a type of carbohydrate known as a sugar alcohol or a polyol. This odorless liquid has a sweet taste and a syrupy consistency. While glycerin occurs naturally in plants through the fermentation of sugars, most of the glycerin nowadays is produced from the hydrolysis of fats and oils.

The first man-made attempt to produce glycerin was in 1779 by K. W. Scheele, a Swedish chemist, when he was boiling a mixture of olive oil and another chemical containing lead. 

The thick, transparent liquid Scheele separated from the oily mixture was called glycerol due to its sweet taste (“glykos” in Greek means sweet). Scheele’s method of preparation was used in the first commercial manufacturing of glycerin, which quickly found uses in many fields, including health care, cosmetics, and food.

Today, the glycerin used in commercial products is at least 95% pure. Many commercially manufactured glycerin products contain different amounts of glycerin and other impurities, including salt, water, and other organic compounds. 

The U.S. Food and Drug Administration (FDA) and other health authorities have certified glycerin as safe for human intake.

Glycerin is a versatile compound with many health benefits.

Skin health. Glycerin is widely regarded as the most effective humectant. Humectants are water-absorbing substances that help keep things moist. This property of glycerin helps retain moisture in the skin. 

A 2017 study showed that glycerin is an effective skin moisturizer. 

The stratum corneum is the outermost layer of the skin and is a vital layer when it comes to retaining moisture within the body. Research shows that applying glycerin to the stratum corneum enhances its ability to retain moisture. A 2021 study found that glycerin not only boosts the stratum corneum's moisture-retaining capabilities but also improves its structure. But more research is needed to understand the mechanisms involved in the effect.

Glycerin also enhances the skin's ability to absorb moisture or water from the surrounding environment. A separate study highlighted glycerin’s protective properties in countering skin irritants. According to this study, glycerin’s affinity to water protects the skin against many irritants and enhances its restorative functions. 

Research suggests that glycerin's restorative function triggers the skin's healing process. The glycerin stored in the stratum corneum helps the skin retain moisture and accelerate wound healing. Glycerin is vital to normalizing the skin layer and its healing.

Relieves constipation. Glycerin has laxative properties, which can be used to treat constipation. Research shows that glycerin has mild stimulant properties that improve your bowel movements and aid the passage of stool. Glycerin acts as a lubricant, drawing water to the hardened stool and helping your bowel muscles push out the waste.

Improves athletic performance. Some research shows glycerin could help improve athletic performance. A 2012 study involving 40 participants found that glycerin supplements enhanced the individual's ability to carry out physical tasks. But taking them led to an increase in body weight. A possible explanation for the weight gain was the water retention effect of glycerin.

A 2011 study revealed that taking glycerin and creatine supplements improved cardiovascular functions. Participants in this study have also gained weight, probably due to water retention.

Glycerin is used in many industries, including skin care, hair care, and oral hygiene. According to a 2019 FDA report, glycerin is the third most-used ingredient in cosmetics after water and fragrance. Glycerin is now in 23,366 products, including:

  • Lipsticks
  • Hair coloring products
  • Bath soaps
  • Detergents
  • Skincare products
  • Tanning products
  • Baby products
  • Eye creams
  • Shaving products
  • Hair conditioners
  • Oral care products
  • Oral medicines
  • Sweetener in candies and cookies (due to its high sugar content)
  • Solvent and preservative in food products
  • Ice cream and toothpaste base (due to its ability to maintain a smooth texture) 

According to the Personal Care Products Council, glycerin was used at concentrations up to 99.4% in some beauty products, indicating its effectiveness in skin care. Moreover, people with meningitis, encephalitis, central nervous system trauma, and stroke are given glycerin intravenously as it helps lower the pressure inside the brain.

Glycerin is a popular humectant that helps retain the moisture content in many products, such as shredded coconut, marshmallows, soft candies, and sweets.

In the pharmaceutical industry, it's widely used as a lubricant and humectant and as an essential ingredient in many cough syrups, ointments, expectorants, anesthetics, and lozenges. Manufacturers also use glycerin to make drug capsules.

Glycerin also treats glaucoma and other eye conditions where there's increased pressure on the eyes. Individuals with acute glaucoma are prescribed oral glycerin to reduce the pressure and carry out medical procedures.

While glycerin has several benefits, rare cases of allergic reactions have been reported. It's important to remember there are different glycerin preparations for adults and children.

A 2016 study reported skin rashes in an individual after applying glycerin. Doctors typically carry out patch tests to check if your skin is sensitive. This involves applying a small amount of glycerin to the skin and waiting to check if there are any adverse reactions.

You can buy pure glycerin in any brick-and-mortar shop or online store. You generally don’t need a medical prescription to buy liquid glycerin. But you should check with your doctor before you use it in any form or any manner, whether externally or orally.