Glycerin this, glycerin that. At the moment of writing this, my hands are slathered with a glycerin- rich cream. Come to think of it, the liquid soap that I use also boasts of containing this amazing glycerin thing. And you know what? My dishwasher soap contains glycerin too! I have a vague idea that, somehow, glycerin is supposed to protect my hands… But that’s about it. But rarely have I ever stopped to think what glycerin is, how it works, and what it actually does. So if you’ve wondered the same, you’ve come to the right place. Today we’ll talk about what glycerin is, what glycerin does, and its role in skincare.
We call it glycerin, but scientists and chemists call it glycerine (with an extra “e” attached at the end), or, alternatively, glycerol. At this point, I think it’s fairly obvious to both of us, dear reader, that glycerin is one of the most commonly used ingredients in skincare, cosmetics, and beauty products. And as I mentioned above, glycerin is also used in many detergents and soaps, making it a staple of hygiene products too. But is glycerin even natural?
Yes, it is. Since it is either derived from plant sources or made in a lab, glycerin can be both natural and synthetic. The natural sources of glycerin include plant oils such as coconut oil, palm oil, or most commonly, soybeans.
The glycerin that comes from animal sources mostly comes from tallow, and is typically used in the cottage industry for making home-made soap. Finally, as we said, glycerin can also be created synthetically and is usually a byproduct of the distillation of petroleum. Due to its high purity, synthetic glycerin is used in many products, although it’s not the most cost-effective glycerin resource.
Technically speaking, glycerin is a humectant. Humectants, also called hygroscopics, are a class of substances that (as the name might tell you) are used for keeping things moist. Humectants, contrary to desiccants, whisk water molecules out of the air and keep them close. As you might imagine, this is what makes glycerin popular - that it acts as a sort of magnet for moisture. Other popular hygroscopics (i.e. humectants) are the so-called AHA acids, such as glycolic acid or lactic acid, and other substances such as sorbitol, sodium hyaluronate, and hyaluronic acid.
What makes glycerin even more popular, though, is its uncanny ability to mimic the so-called NMF factor of human skin. NMF stands for “natural moisturizing factor,” and represents the ideal level of moisture in healthy human skin. Scientists and dermatologists use NMF as the standard to orient themselves when designing, and making new skincare products. The natural moisturizing factor, however, varies with age. Pollution and aging deteriorate NMF, making our bodies slow to regenerate themselves and, which, in turn, loses its capacity to maintain moisturize.
There is some debate on whether glycerin is really so effective at keeping our skin moisturized. The environment plays a huge role in whether the humectant properties of glycerin will express themselves. For example, if the humidity of the air is 65% or less, glycerin suddenly becomes ineffective at whisking water out of the air.
If you wonder what the level of air humidity is in your area, let me just tell you that air humidity of 65% and above is considered high, and a relatively rare phenomenon on planet Earth. Coastal areas will have higher humidity, and will surely meet and exceed the 65% mark during some months (especially if there is rainfall or tropical storms). But otherwise, chances are that the air you find yourself in is less humid than that. Even office buildings that employ humidifiers try to keep the air humidity level anywhere between 30%-60%. This means that most of the glycerin you use will not be effective - at least if used on its own.
So what happens when glycerin can’t whisk water molecules from the air anymore? Well, instead, glycerin starts to draw moisture from your skin, drawing the water molecules to the surface. As you can imagine, this isn’t very desirable, since instead of moisturizing your skin, glycerin can actually dry it up from the inside.
That is also why you may feel like all those glycerin-based soaps and dishwashing detergents leave your hands worse than before. You might also get that familiar but unpleasant, tacky feel on your hands (or whichever skin area you applied glycerin to).
But, there’s no room for panic. Scientists and dermatologists have been aware of this behavior for a while now, which is why they recommend using glycerin in tandem with emollients, or other occlusive substances. This is a common practice when it comes to skincare products, and especially with moisturizers. Adding emollients, such as oils and lipids, to a product that contains glycerin, will make the glycerin more effective. Essentially, these emollients soothe the skin and keep it soft, by acting as a barrier between your skin and the environment. This prevents the water molecules from evaporating, so they’re able to retain the moisture in your skin, while glycerin draws what moisture it can from both outside and inside.
As we explained in the section above, glycerin is a humectant. Its effectiveness, however, depends on the relative air humidity, as well as whether it’s combined with other substances that can enhance its properties. Since glycerin is a powerful moisturizer, it finds a great number of uses in skincare, and is included in a wide variety of skincare products. Here are some of the best uses of glycerin in skincare, as well as some of its best benefits:
And especially so if you live in a tropical area where there is a lot of water vapor to go around. But even if you live elsewhere, glycerin is still effective at whisking moisture from the environment and keeping it close to itself. Since glycerin is, for lack of a better word, selfish when it comes to water molecules, it also acts as a barrier between your skin and the elements. This protective property means that glycerin protects moisture from evaporating, thereby making your skin feel fresher and softer.
Additionally, these properties can be enhanced if glycerin is combined with emollients, or other occlusive substances. Such a combination will make it even more difficult for the water on your skin to evaporate, making your skin feeling soft, fresh, and moisturized - thanks to glycerin. This is why glycerin is used so often in moisturizers and hydrating creams.
One more notable property of glycerin, especially when used in combination with other ingredients, is that it has the ability to boost the skin’s barrier. If you’re wondering what that is, you’re not alone.
The skin barrier refers to the outermost, surface layer of the skin, which is made out of mostly lipids from your natural skin oil (sebum) and epidermis skin cells (or surface skin cells). This so-called skin barrier protects our bodies from the loss of precious electrolytes and water, forming a thin layer that prevents evaporation. A 2017 research study found that when combined with hyaluronic acid and a plant called Centella asiatica, glycerin provides a strong boost to our skin barrier for up to 24 hours after use.
Needless to say, this property of glycerin also makes it very well suited for protecting your skin from irritation and the damaging effects of the elements. You shouldn’t be surprised to see glycerin included in protective hand creams, rejuvenating gels and a wide array of sunscreens.
Scientists have also discovered that glycerin is also effective at boosting the function of aquaporins - microscopic channels that transport water and other nutrients between the cells. Glycerin facilitates the function of aquaporins, which in turn, makes our body - and specifically our skin - way more effective at transporting water molecules around. This results in a rejuvenating effect on our cells, making them well-moisturized and effective.
Aquaporins are also crucial in the transportation of water molecules and other precious nutrients from the lower layers of the skin to the most superficial skin layer called the epidermis. Since glycerin permeates these channels and facilitates the transport of nutrients along aquaporins, it helps your skin become fresh and moisturized. (This is in addition to glycerin’s ability to absorb moisture from the air and basically give it to your skin.) Likewise, this ability of glycerin to “oil up” our aquaporin channels directly contributes to strengthening the skin barrier, thereby adding further protection to our skin.
Since it is naturally-produced, glycerin is one of the safest moisturizers to use, which is why it is included in so many skincare products. Its popularity is mainly based on its amazing property to collect water from the air and keep it close to our skin. If used alone, this may however backfire, and make your skin dry as it draws water from within it. However, this is easily preventable by combining glycerin with emollients and oils, which is the case with most skincare products that make use of it.
Although glycerin is considered safe and non-allergenic, it is always wise to perform a patch test before using it on your skin. And remember - if you experience any irritation or side effects, you should stop using it and consult with your doctor and dermatologist.
This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances, and its goal is to offer a general view of the subject. In case you are suffering from a severe case of acne, you should consult with a dermatologist or a certified medical professional.