Ingredients Dictionary: Glycerin, Glycerine, Vegetable Glycerine

I have already done quite a few posts on the blog about glycerin but as it is a popular and repeating question, here is the dictionary info for it!


What is it? A humectant- i.e it binds water
Where is it derived from? Mainly now from vegetable oil but can also be made from fossil fuel and animal fat
What is its pH? Around 7 (*pH test by me)
Is it water soluble? Very much so. Each unit of glycerin has 3 binding sites for water.
What is the difference between glycerin and vegetable glycerin No difference. One specifies how the glycerin was made.Glycerol is however the undiluted form of glycerin but is quite a specialist product (i.e bought from a lab supplier not on the shop shelf)
What does glycerin do in shampoo and conditioner? Glycerin is not normally added to shampoo. It  is most powerful in a leave in conditioner. As it is a humectant, it creates an artificial humidity around the hair preventing water loss from the hair.
How much glycerin is added? Scientifically 20-25% in water is the ideal starting point. However significantly less is added (as little as 5%)  in reality as 20-25% can feel very oily and sticky
Is glycerin  a major component of hair conditioner? It can be for a leave in conditioner.
Does glycerin do anything to hair itself 1. It creates a feeling of softness
2. It is known to prevent breakage of natural hair (but not relaxed hair or colour treated natural hair)
3. It has been reported to also offer some thermal protection to hair when using heat
Does glycerin penetrate hair? There is no conclusive evidence. There are theories both ways (i.e that it does penetrate hair and that it does not).
Can glycerin absorb water from hair? There is no evidence of this when using glycerin mixed with water. In theory glycerin prefers to hang on to water therefore once mixed with water, it is in its most stable state. 

Sources and extra reading  (references are in the articles):
1. Good stuff in a funny form
2. Glycerin is your friend 
3. Does glycerin penetrate hair or doesn't it?


  1. Thank you for posting this information, I never knew that there wasn't a difference between veggie and normal glycerin.


  2. Thank you, it always had a great effect on my hair in my spritz so now I know why!

  3. Thanks so much for this post. I'm going to go buy some glycerine today and add it to my shea butter mix.

  4. Your welcome ladies.

    De Anna - Make sure you mix your glycerine with water though. Some arm power can then be used to mix it up into the shea butter.

  5. great post Jc! i love this series on ingredients :)

  6. Thank you so much for this post! I have studied some of glycerin's action power in school and I was surprised to read some articled stating glycerin "drags or sucks" water out of the hair to the air... I was totally skeptical. I still am and still use my glycerin in the winter. I believe as long as there are enough water molecules to bind to then it's okay, anyway, you're the scientist :)
    Thanks a bunch again!

  7. Great post! Does castor oil work in much the same way?

  8. Thank you, JC for making this post! I get a lot of questions about the difference between glycerin (available in the pharmacy aisle) and vegetable glycerin. Some may use vegetable glycerin as a sweetener substitute, but I would not eat anything unless it is stated on the packaging that it is for human consumption. Also thank you for dispelling the myth about glycerin "sucking" the water/moisture out of hair (I'm guilty of passing that "information" on because that is what I heard from many people, but no longer. I will share the information you've posted here). I understand now that when I wet my hair prior to using my homemade vegetable glycerin/water mix on my hair that it worked for me and I didn't get the "dry hair" that some others mentioned online. Currently, I'm curious about how the glycerin with water and dew-points relate to natural hair...

  9. Is glycerin better to use in the summer or the winter? Or the same for both?

  10. But why does glycerin (whether it's winter, spring, summer or fall) make my 4a/3c hair feel like hay? It's worst than a strong hold gel in my hair.

  11. Thanks for the comments all!

    Carol - I would not go as far as to say that castor oil is a humectant although it is a popular opinion. In practice it is used as a sealant. It does contain a specific oil - ricinoleic acid - with one strong water attracting group, this does make it quite different from something like coconut or olive oil.

    However strong humectants like glycerin and honey tend to have multiple water attracting groups and tend to very compact (castor oil's ricinioleic acid is quite large in comparison).

    For those asking about summer/winter and humidity/dew points - I do not doubt that some people experience differences, I just do not have a scientific explanation for it because in theory the water bound to glycerin makes glycerin more stable.

    I can only say that if you have experienced it, then trust your hair! Stop using glycerin or try this suggestion from Oyin on BGLH - try applying glycerin before having a shower. The steam should ensure that the glycerin has ample water to bind to.

    However if it still does not work for you, as I said before, trust your hair, find something else!

  12. Thank you so much for sharing this information.

  13. I am finding these ingredient posts so helpful! I'd love to have them all on a spreadsheet to reference when shopping for hair care products. It's such good info, but I can't remember it all. If you ever do something like that (a spreadsheet) please post a link to it!

  14. i would like to try this but i just cant found a plce to buy this that is not online.

  15. Love it!! Your blog is now one of my favorites!

  16. Thanks for the info! This helps me figure out how much veggie glycerin to put in a creamy leave-in I'm making.

  17. Some people do say it makes there hair drier on the winter but like most stuff put in our hair results will not always be the same or work for all. Thanks for this great post I making my own leave in and wondered if it made any difference if I use vegetable glycerin or glycerin.

  18. There is no doubt that Glycerin acts differently on the hair in the Winter, but that doesn't necessarily mean it's bad. Consider this. In the Winter it is cold. Cold hair is denser than warm air. Dense air squeezes moisture out and thus is very dry. Ever heard of Winter "ASH" or ashy skin. That's the resulting effect. The problem with Glycerin in the winter is that some formulations are not balanced well for Winter use and thus will dry your hair out as Glycerin tries to bring a balance between your hair and the air. It ends up pulling moisture from the only place it can get it when the air is naturally dry from being cold. Your hair ends up being the source for Glycerin to extract moisture.

  19. There really is no such thing as regular Glycerin and vegetable Glycerin. In the chemical industry, Glycerin is usually referred to as natural (vegetable) or synthetic (man made). There is very little difference in their performance. I prefer synthetic for reasons that won't matter to you (It has more consistent clarity and is more readily available). The only advantage to natural/vegetable Glycerin is that sometimes it can cost a whole lot less.

  20. Why does Glycerine not prevent breakage in relaxed or color treated hair?


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