What Does Glycerin Do for the Skin?

Dry skin is nobody's idea of a good time. Without enough moisture, skin can feel uncomfortably tight, rough to the touch, look flaky, and get in the way of a smooth makeup application. Whether you only deal with occasional dryness or experience year-round dehydration, products with heavy-hitting moisturizing ingredients are the only thing that will relieve dry, cracked skin.

If this isn't your first rodeo, then you've probably already heard of hyaluronic acid, squalane, and ceramides because they tend to get all the praise and marquee placement on product labels. But there's another extremely hydrating ingredient that's underrated and doesn't always get the credit it deserves: glycerin. Glycerin may not be top of your mind when it comes to all-star moisturizing ingredients, but if you look at the labels on the products in your medicine cabinet, you'll find it's in almost everything.

So what makes glycerin so great that brands put it in so many products? We turned to the experts for a complete breakdown of this ridiculously hydrating ingredient.

What Is Glycerin?

Glycerin is a colorless, thick, viscous liquid found in both plants and animals. In topical skincare, it's derived from plants or synthetic ingredients and used for its hydrating abilities. "It's a humectant that helps to draw moisture into the skin and can smooth the skin," Marisa Garshick, MD, a board-certified dermatologist at MDCS Dermatology. "While it may not always be the main active ingredient in a product, it is often incorporated to help hydrate the skin."

Chris Tomassian, MD, a board-certified dermatologist and founder of The Dermatology Collective, agrees and adds that it can also facilitate skin repair, increase the skin's plumpness, and aid in better penetration of other ingredients. This is why you'll see it as a main ingredient in a lot of products.

Compared to other humectants out there, it isn't the strongest. "It's a poor man's hyaluronic acid when it comes to moisturization for the consumers," adds King. But don't let that fool you into thinking there is no need for glycerin. There are plenty of benefits that come with this key ingredient.

The Benefits of Glycerin for Skin

In case it's not clear yet, glycerin is exceptionally hydrating. But, what also makes it great for dry skin is that its effects last long after you've applied your moisturizer.

"Glycerin is one of a precious few moisturizing ingredients that has a lasting effect, well beyond its time of application and absorption," Dr. Palm explains. "It is now known that glycerin may help enhance aquaporin function in the skin, increasing hydration to the tissue."

Aquaporins are proteins that help maintain the flow of essential hydrating substances (such as water) to the skin's outer layers. A regular flow is vital for skin to maintain its hydration — especially in the winter or drier climates.

The Side Effects of Glycerin

One of the main reasons you should incorporate glycerin into your routine is that it has almost no negative side effects. Both Dr. Garshick and Dr. Tomassian say that glycerin is often safe for all skin types. "There are no known side effects related to glycerin when incorporated into skincare products," says Dr. Garshick.

But as with any new ingredient you're introducing to your routine, she says you'll still want to be mindful, just in case. Do a test patch to see if you have any negative reactions to it. Though rare, Dr. Tomassian says there is a slight chance you might experience irritation if you have an allergy or sensitivity to glycerin.

As always, go to your dermatologist or a licensed professional if you have any questions.

Why Glycerin Is in So Many Skincare Products

"For formulation, the benefits [of glycerin] are that it keeps products from drying out over time and also helps with preservation," says King. "If a product is formulated without water and just glycerin, glycerin also gives a warming sensation."

The cosmetic chemist says that glycerin can also help with preservation to keep products from contamination and makes a great solvent in lieu of "less desirable propylene glycols."

Another reason why glycerin is seemingly in nearly everything? As mentioned before, it works for all skin types. "Glycerin is an extremely well-tolerated, safe, and common ingredient in moisturizers, especially in more sensitive skin types such as eczema or rosacea," says Dr. Palm. "It is extremely unlikely for someone to develop any sort of sensitization to glycerin."

Ingredients to Use with Glycerin

Glycerin not only plays well with other ingredients, experts actually encourage finding products that surround glycerin with other humectants and moisturizing ingredients. Dr. Garshick lists ceramides, squalane, and fatty acids.

The ingredient can also help offset the negative side effects of other harsh ingredients. For example, Dr. Tomassian says you'll see glycerin paired with retinol and exfoliating acid to limit dryness and irritation. Moreover, He adds that glycerin can help boost other ingredients, like antioxidants and niacinamide, to support and protect the skin barrier.

How to Use Glycerin in Your Skincare Routine

You guessed it: Look for a moisturizer with glycerin in it. "Glycerin, as an ingredient with occlusive agents, and other ingredients that restore the skin barrier are a recipe for success for effective moisturizers in skincare products,"  explains Dr. Palm. "The best use is typically once to twice daily, although increased usage may be warranted during low humidity [conditions], after in-office procedures [like lasers], or in patients with dry skin conditions such as eczema or ichthyosis vulgaris."

Dr. Garshick says that glycerin can also be found in toners, cleansers, and serums, where it is combined with other moisturizing ingredients to achieve the greatest benefit. On the toner front, she recommends the Cetaphil Gentle Cleanser or Thayer's Facial Toner. And then Dr. Tomassian recommends Kiehl’s Ultra Facial Cream as it combines glycerin with other moisturizing ingredients like squalane to provide instant hydration.

Dr. Palm recommends asking your dermatologist about what occlusive ingredients (which prevent water loss in the skin) to look for in your product formulas, but mineral oil, petrolatum, lanolin, beeswax, and some plant-based oils such as argan, olive, and safflower are some common examples.

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Frequently Asked Questions

• Is there a certain time of day that is best when incorporating glycerin?

  Dr. Garshick says that you can use it either in the morning or evening and even at both times. It's all based on your personal preference.

• What skin type benefits most from glycerin?

  Glycerin is safe enough to use on all skin types, but Dr. Garshick says it is especially good for those with dry skin.
  

• Does glycerin need to be the main ingredient?

  "No, glycerin is often incorporated into products as an additional ingredient to help boost moisture and hydrate, but does not need to be the main ingredient," says Dr. Garshick.

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