Glycerin is a friend and a foe. In one breath it can be praised but in the next it can be cursed. So here are a few quick facts about glycerin.
1. It is a humectant which means it can hold onto water (3 molecules of water to be precise).
2. It is moisturising i.e it helps maintain or increase water levels of hair.
3. Natural hair treated with glycerin is resistant to premature breakage. This means the hair will break but not as much at low levels of force. Relaxed hair does not benefit from this property (J Soc Cosmet Chem, pg 39-52, 1985).
Why is glycerin so hard to use?
Glycerin is usually quite effective at high levels. High means 20-25% mixed with water (1 part glycerin to 3 or 4 parts water). However this mix tends to feel sticky to the touch. As the scientists say, 'it lacks cosmetic elegance'.
Therefore glycerin is normally changed to very low concentrations (between 2 and 10%) and mixed with additional ingredients such as oil.
Glycerin IS a very effective moisturising ingredient, there is even an entire book dedicated to it. If you need to troubleshoot your glycerin use, consider these tips.
1. Do not use straight glycerin, always combine it with water. Start at around 25% (1 part glycerin to 3 parts water) and keep increasing the water until you find a level you like.
2. Glycerin can feel sticky. Try using a small amount in a spray bottle. Do not thoroughly wet the the hair, just a few short sprays.
3. Glycerin is easily washed off. If you don't like a particular concentration, get rid of it by wetting your hair or washing it.
4. Does your hair feel mushy after using glycerin? It may be because your hair is moisturised enough or you have applied too much product.
As always do share your successful mixes and check out the science bit over here