Home Cosmetic Science Talk Formulating preservative for cosmetic product with pH>10

  • preservative for cosmetic product with pH>10

    Posted by Roni on July 8, 2018 at 1:11 pm

    Hello,

    I have created a formula with more than 80% water, and need preservatives for a pH level 10-11
    any suggestions?

    Thanks!

    Microformulation replied 6 years, 5 months ago 6 Members · 6 Replies
  • 6 Replies
  • belassi

    Member
    July 8, 2018 at 1:42 pm

    You do not need a preservative for that pH but you will need new skin after you use it.

  • Bill_Toge

    Member
    July 10, 2018 at 12:01 am
    phenoxyethanol works well up to about pH 12
    1,2-diols (butylene, pentylene, caprylyl glycol etc.) are also pH independent
  • Roni

    Member
    July 12, 2018 at 10:35 pm

    Thank you

  • mikethair

    Member
    July 14, 2018 at 5:53 am
    If the product is a wash-off then the pH 10-11 will not be a problem. It is a common pH for saponified oil soap washes and soap bars.
    ISO 29621 (Second edition 2017-03) “Cosmetics — Microbiology — Guidelines for the risk assessment and identification of microbiologically low-risk products” covers the pH of formulations. It says “Liquid soaps with alkaline pH (pH 9,0 to pH 10,0) present an environment unfavourable for the growth of some microorganisms. Hair curl relaxers, due to their extreme pH (around 12), prevent the growth of virtually all microorganisms that would be likely to contaminate cosmetic products.”
    However, we always carry out microbiol tests in our lab on every batch produced.
    Hope this helps.
  • Gunther

    Member
    July 16, 2018 at 3:54 pm

    pH 10-11 will damage skin or even hair on contact
    it’s irresponsible to sell such a product, and you’ll likely get sued or prosecuted.

    Just too dangerous for consumers, even for a concentrate product, supposed to be diluted before use.

  • Microformulation

    Member
    July 16, 2018 at 3:59 pm

    Honestly, as @mikethair correctly points out, it is not unusual for a saponified product to be at a pH of 10 or so. In fact, dropping to a pH much lower will destabilize the product and in fact reverse the saponification reaction.

Log in to reply.

Chemists Corner