Glycerine and the Moisturising Abilities of Natural Soap
Glycerine, also known as glycerol, is the less trendy, cousin of hyaluronic acid. It's a clear, colourless, odourless and syrupy liquid with a sweet taste. These days top cosmetic products, especially face creams, contain hyaluronic acid - and this is at the forefront of their marketing. Hyaluronic acid, just like glycerine, is a humectant. Humectants are great for our skin - they attract water and hold it there, supporting your skin barrier and keeping the natural processes and defences functioning as they should be.
Even though hyaluronic acid has been at the forefront of cosmetic marketing in recent years, glycerine is also incredibly effective, but has unfortunately not received the same amount of hype. The key to understanding the difference between these two humectants is their molecular weight. Glycerine has a molecular weight of 92 Daltons (92 grams per mole). Molecules need to be under around 500 Daltons in order to be absorbed by the skin, which is known as the ‘500 Dalton rule’. Under 500 Daltons ensures that molecules can pass between skin cells (and even enter the hair shaft) so it doesn’t just sit on the surface. Hyaluronic acid however has a range of molecular weights starting from 4000 Daltons. So these two molecules act differently on skin due to their molecular weight - hyaluronic acid retains moisture on the surface of the skin, while glycerine has the ability to pull moisture deep into the skin.
So is glycerine a better moisturiser? Well, to be honest, we prefer glycerine over hyaluronic acid - please don’t be angry with us! Hyaluronic acid sits on the surface of your skin, and when it draws in water from its surroundings, it creates a layer of moisture, smoothing out fine lines and wrinkles on the surface and giving a youthful dewy appearance. This is definitely the effect that we are looking for, however it only lasts until the water evaporates. In addition, unfortunately, while it is sitting on your skin, you cannot control where it is absorbing water from - the air or from your skin. If the air is humid, water will mostly be attracted from your surroundings, but if the air is dry, the only water available will be from your skin. Especially in dry environments, hyaluronic acid can result in dehydrated skin.
If you are focused on prolonging the temporary plumping effect of hyaluronic acid before it evaporates, one option is to use it with an occlusive substance, such as a wax or oil, which will create a barrier and temporarily reduce water evaporation. You are still however putting your deeper layers of skin at risk of dehydration by using an occlusive over hyaluronic acid - while the hyaluronic acid sits on the surface of your skin under the occlusive, and plumps up the surface with any water that it can attract, the air is effectively blocked from the hyaluronic acid. The water that the hyaluronic acid attracts will come from your skin, drying it out. In the end, we don’t feel that the temporary plumping effect of hyaluronic acid is worth the risk of dehydrating your skin.
Glycerine however is great for dry skin because it can be absorbed into the deeper layers and hold water there. By sitting inside the skin, evaporation will not happen as much as it does to water which sits on the surface. In this case using an occlusive will prevent any of the little evaporation that will occur, but may not even be necessary anymore, as the skin is already moisturised from within.
So how does this relate to natural soap?
In the soap making process, we combine oils with lye. When combined, a reaction takes place and the ingredients are transformed into soap and glycerine. Around the 1920’s, companies started extracting the glycerine, which is separated from the soap using salt, and used this glycerine in skin and hair products. Glycerine can be sold for more profit in skin and hair products than what would typically be made when sold in the soap. It could be said that the soap industry therefore actually turned into a glycerine industry, with soap as a by-product. The raw soap was then sold without any, or a vastly reduced amount of, glycerine. Soap alone can be quite drying to your skin, as it can be too cleansing and removes the skin’s natural oils. When the glycerine is left in the soap, this balances out the amount of cleaning and moisturising. Unfortunately, over time, bar soap began to get a bad reputation for being drying for skin, but only because it was being sold without the glycerine.
Natural soap is elegant in its simplicity. The ingredients are as close to how they are found in nature as possible. It is not processed after mixing the oils and lye. It is biodegradable, if no artificial colorants or fragrances are used. No preservatives are needed. And most importantly, it contains the full amount of highly moisturising glycerine. Your skin will feel supple and refreshed, and thankful that you are taking care of it using a bar of natural soap.
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