Why did glycerin go out of fashion?
First discovered during the 19th Century, glycerin was a by-product of saponification, a soap-making process that used fatty ingredients. To begin with only animal fats were used to obtain glycerin. Which in turn was used to make candles. The cosmetics industry quickly latched on, but from the turn of this century it was replaced by hyaluronic acid - an active ingredient that proved easier to formulate. The reason? Glycerin is a bit gooey and greasy - not at all like the easily absorbed textures we want from our creams.
Glycerin's rise to power
Nowadays, most anti-ageing facial skincare treatments contain glycerin (usually between 3 and 5%). It's also found in some body creams, shower gels and soaps. So why is it all the rage? Because glycerin is naturally present in the body and therefore suited to all skin types. Because modern glycerin/polymer formulae create gorgeous textures that don't leave our skin feeling sticky. And because it stabilises formulae, meaning products require fewer preservatives to extend their shelf life.
How does glycerin work on skin?
Firstly, it hydrates skin. Glycerin is emollient, humectant and occlusive. Put simply, it quickly penetrates the epidermis where it absorbs several times its weight in water and imitates our skin's natural, hydrating process - something that lessens with age. It traps water in the epidermis by forming an occlusive barrier, meaning our skin doesn't dry out.
Secondly, it's an anti-ageing powerhouse. Glycerin has surfactant properties that smooth skin whilst keeping it well-hydrated. Its moisturising action keeps skin supple and comfortable for longer. So you can kiss goodbye to tight skin!
Thirdly, it repairs skin. Glycerin nurses skin back to health by helping the epidermis to synthesise lipids. It improves skin tone and leaves it feeling wonderfully soft.
Finally, it protects us. Glycerin protects skin from the elements - cold, wind, pollution, UVA rays and so forth. It forms an invisible barrier on skin that prevents these culprits from penetrating the epidermis. It stimulates skin's natural defences, so that aggressive external factors are kept well at bay.