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Home Cosmetic Science Talk Formulating Why does Glycerin reduce viscosity of shampoos?


  • Why does Glycerin reduce viscosity of shampoos?

    Posted by MapX on January 25, 2021 at 8:25 am
    Hi everybody,
    After read many comment in forum about glycerin reduce viscosity of surfactant based product, I want to find out more details about this. Is that effect only in glycerin or other polyols (eg: propylene glycol, polyethylene glycol.. ) and at what concentration does this happen?
    Thank you in advance!
    P/s: Another question xD. How to add conditioning agent in shampoo? I use Amodimethicone (and) Trideceth-10 and Dimethiconol (and) TEA-Dodecylbenzenesulfonate (and) Trideceth-10. Disperse in water or add directly after combine surfactant and thickening agent (SLES/CAPB and PEG-150 distearate, salt) ?
    MapX replied 2 years, 4 months ago 2 Members · 2 Replies
  • 2 Replies
  • chemicalmatt

    January 25, 2021 at 9:55 pm

    Two questions there @MapX, and that second one is worthy of a second post since it will require a looonnnngg answer, perhaps even a seminar (Perry?) so I’ll answer only the first. Glycerine is a polyol just as are diols (propylene glycol), which are all part of the alcohol family. All small-carbon chain alcohols decrease foam and viscosity. PEGs with longer chains do not reduce foam but they will reduce viscosity in most cases. Those hydroxyls act as a tertiary surfactant competing with your longer chain surfactants. David beats Goliath so to speak.

  • MapX

    January 26, 2021 at 2:52 pm

    Thank you @chemicalmatt. If glycerin competing with long chain surfactant, i can still use it in low concentration (maybe 1-2%) for pre-mix with gum, is that right? 
    For 2nd question, I realized conditioning agents have many classes : occlusion, silicone and their derivative, polymers, proteins, cationic surfactant …. So each of them have different way to add in shampoo or skin care product. I will very happy if we got a webinar for this. :smiley: