Home Cosmetic Science Talk Formulating General Propylene Glycol. Nay or Yay?

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  • oldperry

    Member
    May 7, 2020 at 3:48 pm

    Propylene glycol has been determined to be GRAS. (Generally regarded as safe).

    This means it is safe enough to eat.

    No, it’s bad reputation is not warranted. 

    It’s strictly fearmongering likely created by smaller brands to frighten consumers into staying away from products from large brands that use it as a humectant & solvent.  It’s inexpensive, effective, and safe.

  • esthetician922

    Member
    May 7, 2020 at 3:52 pm

    Thank you! Actually, to piggy back this question. If one didn’t want to use Propylene glycol what would be a good substitute?

  • alchemist01

    Member
    May 7, 2020 at 4:21 pm

    Thank you! Actually, to piggy back this question. If one didn’t want to use Propylene glycol what would be a good substitute?

    What are you using it for? Propylene glycol is a multi-faceted ingredient.

    It works as a humectant, so you can substitute with glycerin, sorbitol, PCA, etc. if you need one added in.
    It also works as a preservative enhancer, so you could replace it with ethylhexylglycerin.
    It enhances skin penetration to improve active efficacy, I’m not sure what some alternatives to that could be as I haven’t utilized that aspect of it.
    It also works as a solvent in some systems, and can be replaced with whatever applies.

    If you’re looking for a general replacement that hits most/all of these, I think propanediol, butylene glycol, pentylene glycol (noticing a pattern?) all work similarly. However, propylene glycol works great and is very cheap so I’ve never bothered. 

    I would identify what the role of propylene glycol was initially and figure out how to appropriately replace it.

  • esthetician922

    Member
    May 7, 2020 at 4:24 pm

    It would be used as a humectant in a water based moisturizer/hydrator. Thank you for the feedback! 

  • ngarayeva001

    Member
    May 7, 2020 at 7:50 pm

    As Perry said, it’s safe enough to eat. It’s in medicine and in some food products. But yeah “who wants to put anti-freeze on their face”… 1,2 Propanediol. Same thing but hey, it’s made from corn.

  • ngarayeva001

    Member
    May 7, 2020 at 7:56 pm

    @alchemist01, I read another humectant that works as a penetration enhancer is urea. When it comes to humectants my favourite is actually sodium lactate (it’s similar to sodium PCA but cheaper). Less sticky than glycerin and more hygroscopic. The problem with all of them is that they are electrolytes, so, carbomer gel isn’t an option. I think glycols are great in general, and nothing can beat PG when it comes to the price and functionality.

  • pharma

    Member
    May 8, 2020 at 4:56 am

    But yeah “who wants to put anti-freeze on their face”… 1,2 Propanediol. Same thing but hey, it’s made from corn.

    Antifreeze is traditionally ethylene glycol but PG is also used as a less effective but safer alternative.
    Commercial propylene glycol aka 1,2-propanediol is a 100% fully synthetic petrochemical and not from corn. 1,3-propanediol comes as a version obtained through fermentation of corn but it costs more.
  • ngarayeva001

    Member
    May 8, 2020 at 8:22 am

    @Pharma, my bad. It’s 1,3 propanediol indeed. I used both and I have not noticed any difference in functionality. And I would assume that 1,3 propanediol can be used as antifreeze too. No one does it due to its high price.

  • esthetician922

    Member
    May 8, 2020 at 9:11 pm

    Ok, so just to be clear, when you do see propylene glycol in a formulation we don’t know if it originated from petroleum or corn, right? It would be nice to tell my chemophobe clients it was derived from corn. I guess if I specifically used 1,3 it would be from corn. 

  • ngarayeva001

    Member
    May 8, 2020 at 11:28 pm

    On the list of ingredients  ‘Propylene Glycol’ is 1,2 Propanediol,  ‘Propanediol’ it’s 1,3 Propanediol made of corn.

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