Basic Formulation question I never asked!

Over the years I have found formulas that are written differently.  I am looking at one now that has all the major ingredients listed and they all add up to 100% but 2 ingredients, specifically an "antioxidant" and "perfume" are listed separately with q.s. (as needed) written next to them.  Obviously it would then add up to more than 100% and the perfume, at least, is added the next day.  This would certainly help me in reformulating but I am just wondering about the use of this technique in writing formulas!  Thanks for any assistance you can provide!


  • The quantities involved are so small that the measurement error is regarded as acceptable. For instance "antioxidant" might be 0.02%.
    Design of anti-aging creams, gels, and serums; shampoos; and therapeutic cosmetics. In-house label and box design capability.
  • Thanks, Belassi!  I guess it could also be because the phases that include these ingredients are done the next day?
  • Most formulations I've come across have the major component (water, alcohol, oil, soap base or whatever) listed as " - - to - - - 100" or " - - - ad - - - 100" or " - - - to make - - - 100" or similar such phraseology. Doing this avoids niggly arguments about formulation listings not adding up to 100%.
  • David, most probably not.

    When writing generic formulations like that, "q.s." as an amount for a category like anti-oxidant or fragrance really means "the amount of ingredient that you use in this category  will depend on the required use level for the specific ingredient that you choose. Because it doesn't matter to the formula which ingredient in the category you use, "q.s." directs you to use whatever ingredient you want at the proper level for that specific ingredient."

     The writer assumes that you will deduct the q.s. amount used from the ingredient in the formula that's used at the highest percentage. 

    Directions as to when in the process timing an ingredient is added is virtually never included in the body of the formula itself. If it's needed, it will almost always be in separate manufacturing directions. For example, if an ingredient really needed to be added the next day, that would be spelled out very specifically.
    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."
  • johnb, I have seen some like that but the particular formula I was looking at didn't list the "to 100%) for either ingredient and I have seen others like that.
    Bobzchemist - Thanks for the further explanation.  I have often heard "take it out of the water phase" but not about taking it out of the ingredient that's used at the highest percentage.  But most often that would be the water anyway! :)  I've taken to writing down the manufacturing techniques and timing as well even those these are my formulas but I find it helpful when I go back to make something I haven't made in a while!  Thanks again to everyone for their input!
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