Is l-ascorbic acid soluble in 1,3 propanediol?

So I recently was Black Friday shopping and I came across a serum product consisting of ascorbic acid and alpha arbutin dissolved in propanediol.  This was from a fairly reputable retailer and so my question is if anybody has any specific solubility information about propanediol.  I found some resources from a manufacturer of this ingredient suggesting that it can dissolve much higher amounts of ascorbic acid than propylene glycol, but again, no specifics.  Any information would be really appreciated.  I'm curious to know if any other cosmetic actives can be dissolved in propanediol as well.  


  • The Ordinary. I made a huge mistake of going there on Friday. The product you are referring to has 8% of both if I am not mistaken. Kielhs has a product with 12% of LAA and 3% of some derivative in propanediol. Propanediol is a good solvent in general. You can use it instead of propylene glycol, but propanediol is considered more "skin friendly" ingredient. You can dissolve ingredients like salicylic acid and allantoin in it.
  • MarkBroussardMarkBroussard Member, Professional Chemist

    Yes, Ascorbic Acid is soluble in 1,3-Propanediol at up to 17%.  Much more than that would be pushing the solubility limit and you'll get some precipitate.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • Also it’s a good humectant and reduces tackiness of glycerin. I use it in the most of the lotions I make.
  • Bill_TogeBill_Toge Member, Professional Chemist
    the material commonly called "propanediol" is 1,3-propanediol, while the material commonly called "propylene glycol" is 1,2-propanediol

    in chemical terms they are almost identical, the only substantial difference being their densities and boiling points, but DuPont have patented a sugarcane-based method for manufacturing 1,3-propanediol which wins it some points with the 'green' crowd

    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • Thank you for clarification  @Bill_Toge. I though that 1,2-Propanediol is the same as propylene glycol but wasn’t sure.
  • Some say 1,2 propanediol/PG is (slightly?) more irritating than 1,3 propanediol, because of the lower density/MM.
    I have used both as the main solvent in my liquid 2% salicylic acid exfoliant, but I couldn't tell a difference. 
  • According to Zemea papers the difference in irritating potential seams rather important. Can we believe this?

    It has been hypothesized that dipole moment may influence skin irritation responses, which could provide one explanation for this difference since PDO and PG have different dipole moments—the PDO molecule having greater flexibility.

    I wish I knew what is this flexibility about :D 
  • Thank you @maria. I read those. I can't really say whether it's much better than propylen glycol, but I can say that 1,3 propanediol is a good ingredient in general. I used a couple of product where it's used a a primary humectant.

  • Yes @ngarayeva001 I agree with you and there are more and more products with a lot of propanediol, maybe it's just greenwashing but I like it too.

  • MarkBroussardMarkBroussard Member, Professional Chemist
    It's so popular that there is a 9-month backlog to purchase bulk volumes.  They can't make enough of it fast enough to keep up with demand.
    Chemist/Microbiologist formulating in the Organic & Naturals arena under ECOCert/Natural Products Assn/Whole Foods/National Organic Program guidelines focused skincare & haircare products. 

    See website for details
  • @MarkBroussard,  it’s often out of stock on makingcksmetics and lotioncrafter. So I bought 2 litres not to think about it. I understand 2 litres sounds funny for professionals, but it’s a lot for a homecrafter.
  • you don't need as much solubiliser with propanediol, good solvent, good alternative to people that hate glycerin. The vitamin C to use is Sodium Ascorbyl Phosphate. Hope this helps.
    Dr. Catherine Pratt
    (B.Sc with HONS I , Ph.D Analytical/Organic Chem and Microbiology), Cosmetic Chemistry IPCS)
  • DoreenDoreen Member
    edited November 2018
    It wouldn't surprise me. It's not even the irritating potential for most of the crunchies, the fact alone that PG is being used in anti-freeze makes them anti.
  • My "secret" mix for creams is 2% Butylene Glycol, 1.5% Glycerin, 1% Propanediol. Sometimes I just skip glycerin at all and up Propanediol.
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