Glycerin

The most popular moisturizing ingredient in the world. It is a powerful humectant – cheap yet very effective. Glycerin also has soothing and anti-irritant properties and is considered to be very safe for use.
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Glycerin

What is Glycerin?

Glycerin, also known as glycerol, is one of the oldest and most used skincare ingredients known to man, and rightly so. Glycerin is a simple sugar alcohol compound. This sweet-tasting, clear, syrupy liquid acts as a humectant moisturizing ingredient and can be found in most skincare products on the market. It is a natural part of our body and skin and serves many purposes.

What Is Glycerin Made Of?

Glycerin is a naturally occurring substance, found in both plant and animal fats. Glycerin is produced when these fats undergo a process called saponification - a chemical reaction that occurs when fats are mixed with an alkali, like lye. This reaction produces soap and leaves glycerin as a byproduct.

In the skincare industry, it can be derived from both natural sources, like vegetable oils, or synthesized in a lab. For use in skincare, glycerin is often obtained from plant-based oils. This ingredient is sometimes referred to as ‘vegetable glycerin’. Regardless of its origin, the glycerin used in skincare is chemically identical, offering impressive benefits such as deep hydration and skin soothing properties.

Glycerin in Skincare

Glycerin is a widely used skincare ingredient due to its multifaceted benefits and properties. Here's how it contributes to skincare:

  1. Moisturizing (Humectant): As a humectant, glycerin's key attribute is its ability to attract water from the air and the deeper layers of the skin, locking it into the skin's surface. This powerful moisturizing action results in hydrated, plump, and healthy-looking skin.

  2. Soothing: Glycerin has calming properties, reducing skin inflammation and irritation. It's especially beneficial for sensitive skin, offering relief from redness and discomfort.

  3. Emollient: Acting as an emollient, glycerin helps smooth the skin's surface by filling in tiny micro-cracks, strengthening the skin's barrier, and reducing symptoms of dryness or flakiness.

  4. Solvent: In skincare formulations, glycerin aids in dissolving other ingredients, enhancing the overall effectiveness of the product. Its solvent property ensures a uniform distribution of ingredients, allowing for optimal skincare benefits.

  5. Viscosity Controlling: Glycerin also plays a crucial role in managing a product's viscosity. It helps maintain an ideal balance between fluidity and thickness in skincare products, ensuring smooth application and effective delivery of active ingredients to the skin.

Glycerin For Skin: Benefits, Side Effects, How to Use

The benefits of glycerin in skincare are varied, and quite honestly, pretty incredible for such a simple, accessible, and cheap ingredient. So incredible, in fact, that it happens to be one of the two most popular humectant ingredients in the world, alongside the famous hyaluronic acid.

Glycerin has been shown to help reduce trans-dermal water loss and improve the properties of the skin’s lipid barrier. In other words, after application, this superstar ingredient gets absorbed into the entire stratum corneum (the topmost skin layer), where it goes on to improve the skin’s water-holding capacity and leaves the skin well moisturized.

Glycerin also has soothing and anti-irritant properties, and regular use of the ingredient can result in reduced skin roughness and improvement in the overall feeling of the skin.

Glycerin is able to perform these effects at almost any concentration. Concentrations ranging from 5% to 50% have all been proven in studies to be effective at improving hydration.

Pure 100% glycerin, however, actually has a dehydrating effect on the skin. A study showed that the ingredient in its pure form must be accompanied by a least a bit of water in order for the skin to reap its humectant benefits.

Glycerin’s powerful humectant moisturizing effects make it a key ingredient in the treatment of various dry skin conditions such as eczema and psoriasis.

It has been shown that the ingredient can become even more powerful when formulated with occlusive ingredients such as petrolatum, liquid paraffin, or jojoba oils. This is because while the glycerin brings water to the stratum corneum, the occlusive ingredient prevents it from evaporating from the skin, resulting in overall better moisturization.

Its effects on scars, skin discoloration, or acne, however, are yet to be known.

Glycerin vs. Hyaluronic Acid

Skincare enthusiasts are often curious about how glycerin compares to other ingredients. Some of these inngredients are propylene glycol and, of course, hyaluronic acid. The research may provide some answers.

Propylene glycol is another popular humectant moisturizing ingredient. According to one research, it has more-or-less the same effects on the skin as glycerin, even though it has one less alcoholic group.

There was another study that compared the moisturizing effects of glycerin (at concentrations of 5% and 10%) to various types and concentrations of hyaluronic acid in the same emulsion cream base. The results were incredible. They found that glycerin actually outperformed hyaluronic acid in most tests, even though the moisturizing effects of all the tested formulas were good.

While glycerin was able to immediately moisturize the skin, hyaluronic acid only showed equally good results 24 hours after application.

Is Glycerin Safe for Skin?

Absolutely, glycerin is considered safe (even during pregnancy and breastfeeding). It's non-toxic, non-irritating, and hypoallergenic, making it suitable for all skin types, including sensitive skin.

Science

1
Fluhr, J. W., Darlenski, R., & Surber, C. (2008). Glycerol and the skin: holistic approach to its origin and functions. The British journal of dermatology, 159(1), 23–34.
2
Fluhr, J. W., et al. (1999). Glycerol accelerates recovery of barrier function in vivo. Acta dermato-venereologica, 79(6), 418–421.
3
Chrit, L., et al. (2006). An in vivo randomized study of human skin moisturization by a new confocal Raman fiber-optic microprobe: assessment of a glycerol-based hydration cream. Skin pharmacology and physiology, 19(4), 207–215.
4
Breternitz, M., Kowatzki, D., Langenauer, M., Elsner, P., & Fluhr, J. W. (2008). Placebo-controlled, double-blind, randomized, prospective study of a glycerol-based emollient on eczematous skin in atopic dermatitis: biophysical and clinical evaluation. Skin pharmacology and physiology, 21(1), 39–45.
5
Lodén, M., et al. (2001). Instrumental and dermatologist evaluation of the effect of glycerine and urea on dry skin in atopic dermatitis. Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 7(4), 209–213.
6
Pacifico, A., & Leone, G. (2011). Evaluation of a skin protection cream for dry skin in patients undergoing narrow band UVB phototherapy for psoriasis vulgaris. Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia, 146(3), 179–183.
7
Vaillant, L., Georgescou, G., Rivollier, C., & Delarue, A. (2020). Combined effects of glycerol and petrolatum in an emollient cream: A randomized, double-blind, crossover study in healthy volunteers with dry skin. Journal of cosmetic dermatology, 19(6), 1399–1403.
8
Meyer, J., Marshall, B., Gacula, M., Jr, & Rheins, L. (2008). Evaluation of additive effects of hydrolyzed jojoba (Simmondsia chinensis) esters and glycerol: a preliminary study. Journal of cosmetic dermatology, 7(4), 268–274.
9
Andersen, F., et al. (2007). Comparison of the effect of glycerol and triamcinolone acetonide on cumulative skin irritation in a randomized trial. Journal of the American Academy of Dermatology, 56(2), 228–235.
10
Becker, L. C., et al. (2019). Safety Assessment of Glycerin as Used in Cosmetics. International journal of toxicology, 38(3_suppl), 6S–22S.
11
Brinkmann, I., & Müller-Goymann, C. C. (2005). An attempt to clarify the influence of glycerol, propylene glycol, isopropyl myristate and a combination of propylene glycol and isopropyl myristate on human stratum corneum. Die Pharmazie, 60(3), 215–220.
12
Polaskova, J., Pavlackova, J., & Egner, P. (2015). Effect of vehicle on the performance of active moisturizing substances. Skin research and technology : official journal of International Society for Bioengineering and the Skin (ISBS) [and] International Society for Digital Imaging of Skin (ISDIS) [and] International Society for Skin Imaging (ISSI), 21(4), 403–412.