How do I know which chemical increases or decreases after increasing one thing in formula?

Hello @Perry and other professionals,  

I am doing practice to make formulas after reading the book of @Perry
"How To KnockOff a Cosmetic Formula". Basically I have some questions. 

how do I know how much percentage of each chemical I have to use after reading the ingredients from the product labels? 

Second question,

How do I know which chemical percentage increases or decreases after adding a new chemical in the formula? Like I am creating Vanishing Cream in which I added new chemicals(Borax) so I do not know how much percentage I have to add a new chemical and which chemical percentage will be decreased due to new chemicals. According to my knowledge, I was thinking to decrease water. 

Kindly help me I am stuck on this point. 


  • BelassiBelassi Member
    edited August 18
    how do I know how much percentage of each chemical I have to use after reading the ingredients from the product labels?
      -- This comes from knowing typical use amounts and assumptions about the accuracy of the label. EG if it's a shampoo and I see "sodium benzoate" I'd expect to see 0.1 to 0.5% usage, depending on inclusion of other preservatives.
    Your second question, if you increase the percentage of an ingredient the formula is simply recalculated, typically I use Excel for that.
    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.
  • PerryPerry Administrator, Professional Chemist
    What @Belassi said.  Unless you know the formula, the amount that a company used to make a product is something you have to guess at. If you know information about the chemicals and typical use levels, you'll make better guesses than someone who doesn't.

  • I guess if that was so straightforward anyone could reverse-engineer any cosmetic formula by just reading LOI. It only comes with a lot of reading and experience. And wasting a lot of materials.
  • DamodeDamode Member
    In most cases, labels are not detail E. G I'm using licorice root extract, instead of writing just that, I write the lab content of licorice (vitamin A, amino acid), adding all the lab breakdown of licorice is not the same as adding licorice. Label can only guide you but might not take you to destination.
    If you don't know how to start fresh formula, please consult a in-house formulator, we have them in this forum
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