Hair curling preparation

I am trying to formulate a hair curling product which contains thioglycolic acid and I want to adjust the ph of the finished product between 9.2 to 9.5 I tried to adjust the ph with NaoH but on storage the ph drops( as NaoH is hygroscopic in nature). Now I want to know that what shoud I add to the product to adjust the ph rather than NaoH.


  • @Pallavi123 From looking at other alkaline perm products it seems they use Ammonium Thioglycolate with the pH adjusted using Sodium Hydroxide and/or Ammonium Hydroxide and neutralized with Hydrogen Peroxide.
  • chemicalmattchemicalmatt Member, Professional Chemist
    DO NOT use NaOH to do this, under any circumstances. Sodium thio has a different pKb than other salts and you will cause hair to shed.  Use ammonium hydroxide 28% or AMP-95. Add a little ammonium thio to buffer if you wish, but keep track of total thio assay or else bad things will happen to people's hair.
  • @JonahRay thanks for your reply 
  • @chemicalmatt thanks for your reply but what should be the dilution of (how much % dilute) ammonium hydroxide to be used ?
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