Glycerin is the unsung hero of skincare. It is one of the most effective ingredients for skin moisturization known to science. It helps hydrate and calm down dry, dehydrated and irritated skin. It is also very affordable, and has an excellent safety profile. In fact, it is the number 2 most frequently used ingredients in skincare - just after water. But why don't we hear about it from the beauty industry marketers?
Chemically, glycerin is an alcohol - but of a non-drying kind. It was first discovered in 1779. Since then, it has been used for hundreds of different purposes. For example, in food industry today, it serves as a sweetener (yes, glycerin tastes sweet - in fact, the ingredient’s name comes from the greek word “glykeros”, which means “sweet”) and as a preservative. It is also used in anti-icing and anti-freezing fluids. In medicine, it is used as a laxative, as well as in cough syrups and throat lozenges.
Positive effects of glycerin on skin have been known for about 75 years. Today, glycerin is one of the most frequently used ingredients in skincare products, second only to water.
The reason glycerin is so popular in skincare is its excellent hydration properties. Glycerin attracts and bonds water: it has been shown to absorb 100% of its weight in water. In addition to helping to attract water to the upper layer of the skin, due to its chemical structure, glycerin helps to keep the lipids in the skin barrier liquid (similar to its function in the anti-freezing solutions), and this helps the barrier to be more effective against water loss. Glycerin is also helpful in wound healing and can help calm down skin irritation (most likely, due to its support of the skin barrier function).
You might be surprised to know that glycerin is naturally present in skin. It is synthesized in sebaceous glands and seems to play an important role in the natural hydration of our skin. This might be the reason glycerin works more effectively to restore good hydration level in skin compared to other water-loving chemicals (aka humectants) - especially when glycerin is applied in high concentrations (10-15%). It appears that the simple ability to bind water is not enough to work as an effective hydrator for our skin. It is a good reminder not to fall victim to advertisement of constantly popping up “new superior hydrators”: even if they look promising in a lab, a true hydrating effect on skin can only be confirmed by clinical studies (which the new ingredients almost universally lack).****
Another great properties of glycerin are more economic in nature: it is a very common, not expensive ingredients. Coupled with the fact that it is also one of the most studied and most effective skin hydrators ever, it means that effective moisturizers can be very, very affordable!
Unfortunately, glycerin has one serious flow - at least, in the eyes of the beauty industry marketers. They consider it to be too common and cheap to be sexy enough for skincare front labels. This is why you hear all about wonders of hyaluronic acid (an effective hydrator but not necessarily more effective than glycerin), marine extracts, flower waters and fermented essences in skincare marketing, even though in most cases, it’s glycerin doing the heavy lifting on moisturization front in the formulas.****
All-in-all, glycerin is your best friend if your skin is dry, dehydrated, sensitive, or you simply want to prevent these conditions from happening. You can confidently choose it over most other “fancier” moisturizing ingredients doing a favour to your skin and your wallet.