Glycerine: what you need to know about it.

Glycerine (INCI: Glycerin), also known as glycerol or propanetriol, is a triol aliphatic compound naturally present in the form of esters (glycerides) in all animal and vegetable oils or fats. It is composed of three hydrophilic hydroxyl groups of the alcohol type (trialcohol), which are responsible for its solubility in water and its hygroscopic nature. Its name comes from the Greek "glykeròs" which means "sweet". Glycerine was reportedly discovered accidentally in 1779 by a Swedish chemist, Karl Wilhelm SCHEELE, by heating a mixture of olive oil and lead monoxide. This was the first recorded chemical isolation of glycerol and was initially called the "sweet principle of fat". It was not until 1836 that its chemical formula (C3H8O3) was elucidated by a French scientist, PELOUZE. Little appreciated at the time of its discovery, it only gained economic and commercial importance at the end of the 19thcentury when Alfred NOBEL used it for the first time in the manufacture of dynamite. Later, the French pharmacist Paul-Antoine CAP popularised the use of glycerine-based preparations in medicine.

Glycerine is a compound that can be derived from either animal or vegetable fats. These fats undergo a saponification or a trans-esterification. These are common steps in the manufacturing processes of soap and biodiesel. Indeed, most vegetable glycerine is a by-product of industrial chemical reactions. These involve heating the fats under pressure or with an alkaline (lye) or alcoholic solution. This process results in the separation of glycerine from fatty acids, forming a clear, odourless, slightly sweet liquid with a consistency similar to that of syrup. As for vegetable glycerine, it is made from vegetable oils rich in triglycerides (palm kernel oil, soybean oil, coconut oil, sunflower oil, etc.). As for animal glycerine, it is most often derived from beef or chicken fat. Unless specifically stated by the manufacturer, all three types of glycerine have the same INCI designation "Glycerin" in the ingredient list.

Glycerine can also be produced synthetically. It is derived from petrochemical derivatives of petroleum (allyl chloride, acrolein, propylene oxide, epichlorohydrin, etc.). However, it is worth noting that the use of this synthetic glycerine in skincare has been declining in recent years.

A versatile chemical, the glycerine has effects that go beyond the mere increase in skin hydration attributed to its humectant action. It enhances the quality of the skin and hair through various actions.

• Improving theskin's hydration : The moisturising action of glycerine operates on two levels. It retains water within the tissues, thereby slowing down insensible water loss and enhancing the level of skin hydration. Furthermore, glycerol also has an occlusive action. It forms a hydrolipidic film on the surface of the epidermis, which limits water "leakage" and moisture loss.

• Alleviating skin irritations: By combating dehydration and flaking, glycerine soothes and reduces irritations and feelings of discomfort that may be associated with these phenomena. Known for its emollient properties, it promotes the flexibility and elasticity of the skin, which becomes comfortable again.

• Promoting wound healing: By encouraging the synthesis of lipids and maintaining the integrity of the epidermal cells, glycerine activates the skin's repair process when it is injured or damaged. It is therefore recommended for treating rough skin, skin that has been sunburned, or skin with a tendency towards atopy.

• Contributing to cell renewal: While glycerin does not have an exfoliating effect like glycolic acid, for instance, it still enables the skin to shed its dead cells more efficiently. It thus contributes to a good renewal of the cells in the corneal layer.

• Protecting the skin from external aggressions: By forming and strengthening the hydrolipidic film of the epidermis, glycerine acts as a protective agent against external aggressions. It also ensures better cohesion of cells, which contributes to the restoration of the skin's natural defences.

• Acting as a vehicle in cosmetic preparations: Glycerine is very often used to facilitate the extraction of active ingredients.

When applied topically, glycerine appears to be well tolerated by all skin types. It is generally regarded as a safe ingredient, non-irritating and non-sensitising. That being said, an allergic reaction can occur. Some studies to date have reported cases of contact dermatitis (redness, heat, itching) after applying glycerine-based skincare, although this remains rare. However, this risk is higher if pure glycerine is applied directly to the skin. Therefore, it is preferable to use cosmetic products that have incorporated glycerol into their formula.

Highly popular in the cosmetic industry for its moisturising properties, the glycerine is almost systematically used in various product ranges, such as skincare, makeup products, haircare and oral hygiene products. At Typology, it is primarily found in certain facial and body skincare products, whether for normal or sensitive skin.

• From birth onwards, our cica-repairing balm for face and body is a skin repair accelerator with a pro-massaging texture. Recommended for superficial skin alterations, it regenerates skin cells and reduces signs of inflammation (redness and irritation) thanks to the Centella asiatica (INCI: Centella Asiatica Leaf Cell Extract), promotes the reconstruction of the damaged protective barrier with the help of glycerine andbaobab oil (INCI: Adansonia Digitata Seed), creating a "bandage" effect, limits bacterial adhesion with the copper/zinc complex (INCI: Zinc Sulfate, Copper Sulfate), while reducing red or brown scar marks. The result? Skin regains suppleness and comfort.

• An essential product for daily use, our 9-ingredient face cream fulfils its moisturising function for healthy skin. Developed for all skin types, it has been designed with only nine ingredients includinghyaluronic acid (INCI: Sodium Hyaluronate), vegetable-derived glycerine andcoconut oil (INCI: Cocos Nucifera (Coconut) Oil). Pleasant to use, the skin feels comfortable and is instantly hydrated.

• Minimalist, our 10-ingredient body moisturising cream is free from all questionable ingredients (silicones, mineral oils, fragrances, etc.). This cream takes care of your skin with its moisturising and emollient action. It's the complementarity of two key ingredients in the formula that helps to effectively hydrate the body's skin for an immediate soothing sensation and protection. Glycerine aids in maintaining hydration by limiting water loss, while coconut oil forms a protective barrier to ward off external aggressions.

As a vegan brand with a strong environmental conscience, we do not use animal or synthetic glycerine. We favour plant-based glycerine in our skincare products, derived from botanical extracts (corn oil, palm oil, rapeseed oil, etc.).

• SURBER C. & al. Glycerol and the skin: holistic approach to its origin and functions. British Journal of Dermatology (2008).

• HELDRETH B. & al. Safety assessment of glycerin as used in cosmetics. International Journal of Toxicology (2019).