What is Glycerine?

Daniel Judd BSc MBiol


What is Glycerine?

Glycerine (otherwise known as glycerin or glycerol) is a small, naturally occurring molecule that is used in a wide range of products including cosmetics, medicine and food. It is a thick, colourless, odourless, sweet tasting liquid that is used in cosmetics as thickener, and humecant or moisturiser. It is often recommended for people with very dry skin.

When you think ‘fat’, a lot of the fat you’re thinking of is actually three fatty acid molecules stuck on to a glycerine molecule. By getting rid of the fatty acids,  a pure glycerine can be produced. It can be made from either animal or plant fat so products containing it can still be vegan friendly.

This removal of fatty acids is the same process used to make soaps, and unless it is removed afterwards, soap will contain it. This is sometimes labelled as ‘glycerine soap’. Some manufacturers do remove it from their soap so that it can be used in other products.


How does it work?

Glycerine works as a humectant thanks to its chemical structure. Humectants are moisturising chemicals that grab and hold onto water. This improves the water retention ability of the skin when applied topically – helping to moisturise it. It has three water holding ‘hydroxyl’ groups on each molecule making it a great moisture magnet. It increases your skin’s ability to retain water and can help prevent dry and cracked skin.

It is also very viscous so it can increase the thickness of products it’s mixed into. It is used in liquid products to give them a better consistency and also in some icing for cakes to keep them soft.



Side effects:

Glycerine is a colourless and non-toxic additive that is normally well tolerated since it is a crucial molecule in your body. However in some instances it may cause redness, stinging, itching or burning where applied.

Interactions with other medicines:

There are no known drug interactions with topically applied glycerine.


Other names for glycerine

Glycerin,  Propanetriol, 1,2,3-Trihydroxypropane, 1,2,3-Propanetriol, Glycyl alcohol, Glysanin, Glyrol, glycerol