Thickening 1,3-propanediol

Dear Cosmetics formulators,

I am developing a high active serum, and my solvent is 1,3-propanediol (Zemea). So, there is no water. I am looking for a way to thicken it to a consistency of honey. So that it is not yet a gel, but does hold some shape and some body.

Does anybody have any idea, how to tackle such a challenge?

Thank you in advance,
Olja Reven, PhD


  • Silica powder should work, not sure if it will maintain clarity
  • PharmaPharma Member, Pharmacist
    You could try hydroxypropyl cellulose, ethyl cellulose, or hydroxyethyl cellulose. They should be soluble in 1,3-propanediol although, quite frankly, I'm not sure if they also thicken, let alone gel, that solvent without any water present.
    Or use a high molecular weight PEG.
    And there's another strategy which results in honey-like liquids... unfortunately, these are sticky like honey, often coloured like honey, but alas don't smells like honey (it's usually more of a fishy, stall, and/or unpleasant hard to describe smell which you will have to mask with perfume) and require up to ~50% additive depending on the ingredient used for the trick... furthermore, these might be patent protected and if not, then I'm not giving it away for free, not this time.
  • ozgirlozgirl Member, PCF student
    Some Carbopol polymers can be used to create anhydrous glycerine gels so you might be able to try this with propanediol.
  • BelassiBelassi Member, PCF student
    You will have to experiment. Obviously Glucamate LT or VLT would be useless because they are dissolved in propanediol. Although, wait... as supplied, Glucamate VLT has exactly the consistency you require. You could try using it as a direct replacement for propanediol, and add small amounts of water to thicken it. (It produces very thick solutions at around 4 to 5% of GVLT)
    The price, though...
    Cosmetic Brand Creation. Concept to name to IMPI search to logo and brand registration. In-house graphic design inc. Pantone specs. Cosmetic label and box design & graphics.
  • Some time ago I made a gel with glycerin and Lecigel but it did have a small amount of water from glycerin. Also after reading your post I've tried gelling propanediol with sepinov emt 10, and overnight it turned into a nice clear gel. It was quite sticky though.
  • Bill_TogeBill_Toge Member, Professional Chemist
    generally speaking, polymers which thicken water will also thicken glycerine, propylene glycol and 1,2-propanediol, but they'll hydrate much more slowly than they do in water, and may require heat
    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
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