- A natural moisturizer that’s also in our skin
- Super common, used for more than 50 years
- Not only a simple moisturizer but plays an important role in keeping the stuff between our skin cells healthy
- High-glycerin moisturizers are awesome for treating severely dry skin
Glycerin doesn’t sound very glamorous but it is a real oldie but a goodie. It’s been used in cosmetics for more than 50 years and it’s a totally natural ingredient that’s also in the outermost layer of our skin (called stratum corneum - SC).
It’s a so-called humectant type of moisturiser meaning that it helps our skin to cling onto water. A 2005 study has shown that glycerin levels correlate with skin hydration levels, so more glycerin means better hydrated skin.
As newer studies examine glycerin it turns out more and more that it’s not just a simple humectant but also does some other important things:
- It makes sure that the stuff between the skin cells is neither too diluted nor too concentrated (it’s called osmoregulation).
- It helps to maintain the healthy state of the cell membranes and intracellular lipids
- It can normalize skin shedding in very dry skin.
So what this all means is that glycerin is a real goodie and helps maintain the healthy state of our skin in several ways.
And there is even more. If your skin is severely dry, you have to read this. A large-scale study done with 394 guys and girls with dry skin compared two high-glycerin (containing 25% and 40% glycerin) moisturizers to 16 other popular moisturizers on the market (that had less than 6% glycerin). The two high-glycerin ones won hands down. They had superior, quick-acting hydrating properties and they also seemed to create a “reservoir” of moisture-holding ability in the skin. This means that even after not using the high-glycerin moisturizer the skin stayed hydrated longer compared to all the other low glycerin moisturizers.
You might think now that this is sooo awsome I will go to the pharmacy right now buy some glycerin and put it on my face. Well, do not do that. 100% pure glycerin is not good for the skin either. Too much glycerin (and in general humectants) might attract water out of the lower layers of the skin. That’s a problem because once water is in the upper layer some of it will evaporate. It’s called trans-epidermal-water-loss (TEWL). If too much TEWL happens your skin becomes dry. :(
This is confirmed by a study too: skin treated to 99.7% glycerin for 5 days showed that after the treatment the SC (do you remember? it’s the outermost layer of the skin) was not visibly different from the untreated control. The same study also examined skin treated with a 25% glycerin lotion and there the SC had a visibly different, expanded - in other words more hydrated - appearance.
So bottom line: glycerin is a real goodie and newer studies show that it might be more important for skin that we thought before. If your skin is very dry it’s a good idea to try out a high-glycerin (20-40%) moisturizer.
- Leslie Baumann, MD, Cosmetic Dermatology, 2nd edition, Glycerin- pages 275
- The Journal of investigative dermatology., 2005 Aug;125(2):288-93., Is endogenous glycerol a determinant of stratum corneum hydration in humans?
- Dry Skin and Moisturizers: Chemistry and Function, Marie Loden, Howard I. Maibach, chapte 18: Glycerin: a natural ingredient for moisturizing dry skin