Sodium stearate, sodium hydroxide, stearic acid, and mascara

Hey all,
I'm trying to formulate a mascara for a client who has some really, uh, weird constraints. No more than 15 ingredients (excluding "may contains") and nothing over a 2 on the EWG database. If it were up to me I'd tell the client to pound sand as this is necessarily hard (or maybe impossible!) to get a volumizing, lengthening mascara with such constraints but it's not up to me.

Thankfully we already have a formulation that *almost* fits. The main issue is the stearic acid, to be neutralized by sodium hydroxide. Sodium hydroxide is a 3 on the EWG. TEA is a 5 or 6, so we straight up can't neutralize the stearic acid with these arbitrary constraints. 

What about using sodium stearate? Isn't that the endgame for neutralizing stearic acid with NaOH? Using sodium stearate would essentially skip a step. is this feasible or not?


  • Yes using sodium stearate is correct.Good luck as we have done some EWG projects.
  • BobzchemistBobzchemist Member, PCF student
    Yes, sodium stearate is exactly what you get when mixing stearic acid with NaOH. It's more convenient, too. The only reason not to use it is cost - sodium stearate is 2x-3x more expensive than the cost of making it yourself in-situ.
    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."
  • Thanks everyone, I hoped that could be a feasible solution (technologically, at least). Sucks that it's expensive but maybe they'll still be on board.
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