Why use stearic acid?

It's one of those ingredients I don't quite get, to thicken the formula? Are there any skin benefits? Enhance emulsion stability? 

Why not just use e.g. cetyl alcohol instead?


Comments

  • sensorials. Gives a 'cold' effect, e.g. Nivea "Cold Cream".
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  • ZinkZink Member
    But it doesn't actually have any positive effects beyond that?
  • I suppose I am guilty of putting stuff in because it seems to be what everyone else puts in.
    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.
  • Stearic acid is also an occlusive agent, though not as effective as, say, petrolatum.
  • PerryPerry Administrator, Professional Chemist
    It's an emulsifier really.  Typically, you use it and then neutralize it to create an emulsion.  
  • Chemist77Chemist77 Member, PCF student
    edited April 2015
    @Belassi I like your logic the best  :-)

    Actually @Zink is right in asking why stearic acid and why not cetyl alcohol. But it's really matter of choice and the kind of formula you are looking to develop, it's a wholesome thing you consider. Sometimes it fits the scheme and at times you can replace it, just a loud thought. 
  • BobzchemistBobzchemist Member, PCF student
    There's something to be said for using it just because it's convenient, too. It has it's widest use as an emulsifier when it's neutralized - but, if you're already using it as an emulsifier, sometimes it's just easier to also use it as a viscosifier/bodying agent instead of going through the somewhat involved process of bringing in a new material and/or supplier.
    Robert Zonis, Sr. Formulation Chemist, Beaumont Products "All opinions and comments expressed are my own, have no relation to Beaumont Products, are fully copyrighted, and may not be used without written permission."
  • pmapma Member
    edited April 2015
    Unilever has been using stearic acid for a different purpose: replenishing the stearic acid that is highly removed during by surfactants:



    Since their cleansers has a pH around 7, the stearic acid that can be found in their products isn't necessarily saponificated. 
  • ZinkZink Member
    Looks like I'm not the first to ask this questons:

    http://swiftcraftymonkey.blogspot.com/2009/07/cetyl-alcohol-vs-stearic-acid.html

    Seems like the only conclusion I can find is that stearic acid creates a lotion with more drag, good for e.g. foot creams, wheareas cetyl alcohol provides more glide. 
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