Key Takeaways

• Glycerin, also called “glycerol,” is a humectant, an ingredient that can help draw water toward the skin’s outermost layer.

• A 2022 review in Medicina names water-soluble polyalcohols, Glycerin among them, as the most common humectants used in cosmetics.

• The same review notes that humectants are usually paired with an occlusive ingredient, since water loss can increase when a humectant is used alone.

• The American Academy of Dermatology lists Glycerin among the ingredients to look for in a cream or ointment for dry-feeling skin.

What Glycerin Does in a Moisturizer

Glycerin is a water-loving ingredient that shows up in many moisturizers. Labels and references spell it a few ways, including “glycerin,” “glycerine,” and “glycerol,” and all three name the same compound.

Its job is to act as a humectant. A 2022 review of moisturizers in Medicina defines humectants as substances that, applied to the skin, “pull both moisture in the atmosphere and moisture below the stratum corneum toward the stratum corneum,” the skin’s outermost layer. The review calls Glycerin “a powerful humectant” with “similar hygroscopicity to natural moisturizing factors,” meaning it attracts water in a way that resembles the water-binding compounds skin makes on its own.

In everyday terms, Glycerin can help skin look and feel more hydrated.

Why Glycerin Is Usually Paired With Other Ingredients

A humectant pulls water in, but it doesn’t stop that water from leaving. The Medicina review puts it plainly: “Because transepidermal moisture loss can increase when a humectant is applied alone, humectants are usually used together with an occlusive agent.” Occlusives form a thin film that slows evaporation, so the two jobs complement each other. The difference between hydrating and moisturizing covers how humectants, emollients, and occlusives split the work.

Timing can help too. The American Academy of Dermatology’s tips for dry skin suggest applying moisturizer while skin is still damp, and they list Glycerin alongside Hyaluronic Acid, Dimethicone, Petrolatum, and Shea Butter as ingredients to look for in a cream or ointment.

How to Spot Glycerin on a Label

On an ingredient list, Glycerin’s position gives a rough sense of how much of it a formula contains, at least down to the 1% mark, below which US and EU labeling rules let ingredients appear in any order. The Medicina review notes that because ingredients are listed by concentration, the order lets you judge “to some extent” whether a moisturizer is built mainly around sealing ingredients or humectants. A cream with Glycerin high up and an occlusive close behind may be covering both jobs. For a wider look at water-binding formulas, see this roundup of Hyaluronic Acid moisturizers.

Frequently Asked Questions

Is Glycerin the Same as Hyaluronic Acid?

No. They’re different ingredients, but the Medicina review lists both as humectants, and the AAD names both among ingredients to look for in a moisturizer for dry-feeling skin.

Does Glycerin Work in Cold, Dry Air?

Timing matters here. The Medicina review warns that humectant-led moisturizers can let skin lose moisture when it meets cold, dry air after application. It recommends applying them about 30 minutes before heading out into those conditions, or choosing a formula with an occlusive ingredient if you’ll be outside right away.