Shampoo Concentrate - Preservative question

I'm planning to make a shampoo concentrate where the end-user can add water.  I'm hoping to have a 5:1 dilution or let the user add 20% concentrate and 80% water.  So thinking I need 5 times the amount of preservative to keep this safe.  BUT... government regulations don't allow that high of a preservative concentration in a finished product.  I'd appreciate some thoughts on how much preservative to concentrate!  I'm currently using Geogard Ultra at 2% in the diluted product.  Thank you!


  • chemicalmattchemicalmatt Member, Professional Chemist
    The diluted product IS the finished product as applied to humans, so you are OK as long as you do the math right.  More importantly is your solubility limit with that preservative blend. Can 10% even stay soluble? Good 'ol Kathon should solve that problem: 0.25% should go into that easily.
  • The active ingredients in KATHON™ CG Preservative are isothiazolinones 
     :'(   :#  
    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.
  • Sorry for my slow reply and thank you for the responses!  Definitely couldn't use Kathon in our formula.  The Geogard does go into solution and so far hasn't settled out (thanks for that tip to watch for!)
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