Glycerine- a common and age old ingredient on many cosmetic products (and also some food products). One of the most well known use for glycerin is in clear soaps. So what is it, where does it come from, why is it used and do we need it in our skin care????
I am writing this from a skin care formulators/consumers perspective rather than a detailed chemical treatise on it. We started using a vegetarian source of glycerin in micro amounts in some of our products to act as a carrier for a couple of water insoluble ingredients. The previous coconut oils based liquid emulsifier we used was found wanting, and contained too many synthetics for our philosophy. Glycerine seemed the most acceptable and cost effective replacement as it had the characteristics of being odorless, colourless and easy to work with. However time has moved on and more details have emerged which has left this ingredient wanting, in my opinion. Time for some more digging....
The main way glycerine is produced is through the process of soap making as part of saponification. Soaps can be made from either animal or vegetable fats, thus the glycerine produced may not be vegetarian. In addition to this, many soaps are made from palm oil, so again if a consumer is trying to avoid palm oil derived products this furtehr raises the question about the source of glycerine.
As a product glycerin (glycerol) is a odorless, colourless viscous liquid. It has been assigned the E number E422. It can also be added to propylene glycol (anti freeze) and used as a humectant for the skin. Within the food industry glycerol is widely used as an emulsifier and used in margarine, shortenings, ice creams. Sometimes it is approve dfor use as a sweetener in low carb diets due to its low glycaemic index.
In herbal medicine it is widely used as a solvent for raw herbal material, especially where it is desirable to avoid alcohol.
As an aside glycerin is also a key part of the manufacturing of gunpowder and other explosive materials as well as some cardiac (heart) medication.Wikipedia has a great page full of all the technical specs relating to glycerine (http://en.wikipedia.org/wiki/Glycerol).
It seems as if the commercial production of glycerol was around the 1880’s and initially was part of the candle (tallow) industry) and then production increased along with the need for gunpowder.
The technical properties of glycerine are that it has 3 alcoholic hydroxyl groups which accounts for its solubility in water. It is also considered ‘hydroscopic’, meaning that it absorbs water from the air. there is now added concern of the apparent glut of glycerine produced as a waste product of the bio diesel industry. It seems that since 2005 there has been a decreasing price and increasing stock piles of this ingredient due to the bio diesel industry.
Are there any risks to using glycerine in skin care? Whilst there is some concern around the ingestion of large amounts of glycerine, these risks do not appear to be the same for applying through the skin. Due to the size of the glycerine molecule it is not absorbed through the skin. However, there are some considerations oif you are desiring a natural skin care product. Glycerine listed by itself on a label, with out any qualifier could be from any source (animal, vegetable, synthetic). Also it is a cheap ingredient and could be used to pad out a product. Whilst it does have some moisturizing and protecting qualities, the converse is sometimes true if too much is used in a product.
Vegetarians/Vegans and those with environmental concerns will want to know whether the glycerine is from plant sources, and whether it is from palm oil (Orangutan friendly) or form non GMO crops. Suppliers may not be able to guarantee this.
From a formulators point of view we have decided to remove this ingredient from our formulae, even though we know our ingredient meets all the credentials. Its emollient and solvency actions can be replaced by other ingredients which have been ‘fiddled’ with less and therefore can be considered plant derived.