Dear CurlySuzy: While reading about dew point and humectants and looking to test out products without humectants for this winter (because in some climates, there is some risk of the humectant actually removing moisture from the hair, creating the problem it was intended to prevent— read more here), I found myself in doubt about this: is glycerin and vegetable glycerin the same thing? Do they perform the same way?
Dear Cíntia: Yes, glycerin and vegetable glycerin are usually the same thing. Some hair care companies will specify where the glycerin is derived from and list it as vegetable glycerin. In most cases when it says glycerin, it is vegetable derived. This is because vegetable glycerin is the cheapest and the most readily available to manufacturers. In vegan products, the glycerin would be derived from a vegetable base, as well.
Animal-fat based glycerin is not used as much. The soap-making process, from which glycerin comes, is almost always vegetable-based instead of animal-based.
The big time manufacturers could use petroleum-based glycerin. I am not sure which ones and what products those would be. Some companies list the ingredients, some don’t.
Glycerin—any glycerin—is a humectant in most products. The only time it is not a humectant and can be an emollient is when it is used in very, very small amounts.
I hope this helps. I was confused until I got all the facts straight—hope it make sense to you!
Please email me if you have any more questions.