Uses, Benefits, and Side Effects

Glycerin, or glycerol, is a carbohydrate added to skincare, medications, and foods. Glycerin can help sweeten, preserve, thicken, and improve the texture of foods, supplements, and medication. Glycerin also has water-retaining properties that can help moisturize the skin and eyes and relieve constipation. 

Glycerin is a sugar alcohol, a carbohydrate found in fruits, beverages, and other foods. Glycerin is also a significant component of triglycerides (fat found naturally in your body). Pure glycerin looks like a thick and transparent liquid. Because it is a sugar alcohol, glycerin has a sweet taste. 

Glycerin can be found naturally in plants from fermenting plant sugars. However, most glycerin is manufactured using a process called hydrolysis. During hydrolysis, glycerin is extracted from broken-down vegetable oils and animal fats using water or chemicals. Glycerin can also be created synthetically using petroleum.

Glycerin has a variety of uses in skincare, medicine, and food products. As a sugar alcohol, glycerin can sweeten foods, drinks, supplements, and medications. It can also help thicken and preserve some foods and cough syrups.

Because glycerin is a humectant (a substance that attracts water), it is added to skincare, soap, eye drops, and cosmetics to help retain moisture. Glycerin can help lotion moisturize your skin, or eyedrops add moisture and lubrication to dry eyes. Glycerin’s emollient (softening) properties also help create a layer on top of the skin to trap moisture and soften the skin.

Glycerin can increase hydration when added to sports and energy drinks. It can help food retain moisture and the body retain water. The humectant also helps cough syrups coat and lubricate your throat while treating a cold.

Glycerin is also used as a solvent in cosmetics and medications, helping to dissolve ingredients that don’t mix well with water or extract certain chemicals.

Glycerin can offer hydrating and moisturizing benefits to the skin and is often added to skincare products. Glycerin can also help prevent dry eyes and improve digestion, mainly due to its ability to help tissues retain water.

Skin

Studies have found that glycerin helps relieve dry skin, repairs the skin barrier, and aids in wound healing. Glycerin is an excellent moisturizer because it is a humectant and an emollient, meaning it brings water into your skin and soothes the top layer of your skin. When applied topically, glycerin lubricates the outer layer of your skin (epidermis) to keep water in and avoid dryness.

Eyes

Applying eye drops with glycerin can add moisture to dry eyes to reduce discomfort and lubricate the eye. Glycerin’s humectant properties help eye tissues retain moisture.

Digestive Health 

Glycerin can relieve constipation when taken as a rectal suppository. When inserted into the rectum, glycerin helps increase the water content of your intestines. It has a laxative effect and softens stool for smoother bowel movements. Glycerin can also improve bowel muscle contractions to help you poop.

Endurance

Limited evidence suggests that ingesting glycerin may help improve athletic performance. Some research indicates that glycerin can help athletes retain water and reduce fluid loss due to sweating. This may improve endurance, which often decreases due to dehydration and fluid loss.

A small study found that soccer players who ingested glycerin had better endurance and overall athletic performance than participants who did not. However, some participants also experienced increased body weight.

Glycerin is considered safe when ingested in 30 milliliter (mL) doses or applied topically. The United States Food and Drug Administration (FDA) lists glycerin as a generally recognized as safe (GRAS) substance. 

It is still possible to experience side effects when using glycerin. In rare cases, people have experienced allergic reactions to ingesting and applying glycerol. It can cause skin rash and irritation. Some people may also experience burning or stinging when applied to their eyes.

Because glycerin retains moisture, it can also have a dehydrating effect when taken orally—especially if taken in large doses. Consult your healthcare provider about the recommended dosage for you. Symptoms from glycerin dehydration include headaches, dizziness, nausea, diarrhea, and vomiting.

The lowest lethal dose (LDLo) of glycerol is considered 1,428 milligrams per kilogram (mg/kg). Glycerin can be toxic in humans if it exceeds this dosage. 

Choose glycerin products based on your needs. You can find glycerin in over-the-counter (OTC) food, skincare, and medical products at most supermarkets, drugstores, or supplement stores.

Glycerin is an ingredient in cosmetics, creams, lotions, soap, and eye drops. Pure liquid glycerin can be applied directly to the skin as a moisturizer. For constipation, you can purchase glycerin rectal suppositories.

When choosing a glycerin product, some manufacturers will list it as vegetable, animal, or synthetic glycerin. If you’re concerned about artificial ingredients, you can seek more information about the product’s manufacturer.

Glycerin has moisturizing and hydrating properties that can help moisturize the skin, relieve constipation, and prevent eye dryness. You can find glycerin in many skincare products and medications. It is possible to have an allergic reaction and experience skin irritation, dehydration, and other symptoms from using glycerin.