Safety of Multiple Whitening Ingredients in Cream: Total vs. Individual Percentage
Question
I understand that for a cream formulation containing multiple whitening ingredients, the basic principle is to keep the total percentage of these ingredients not exceeding 25%, and the quantity of each individual ingredient not exceeding its recommended maximum usage level. Is this understanding correct? I've seen formulations with a much higher total percentage of ingredients.
Answer
Based on the discussion, the safety of using multiple whitening ingredients in a cream formulation primarily depends on the maximum recommended usage level for each individual ingredient, not the total combined percentage.
The 25% guideline mentioned is generally a recommendation to help achieve a pleasant texture and avoid stickiness, especially for beginners. A total percentage higher than 25% (like your 35%) might result in a heavy or sticky texture, but it is not inherently unsafe if each ingredient's concentration is within its own safe limit.
To ensure safety, you should verify the maximum recommended usage percentage for each specific ingredient you plan to use (Alpha Arbutin, Azelaic Acid, NanoWhite, etc.). As long as each ingredient is used at or below its recommended maximum, the formulation is generally considered safe from a toxicity standpoint.
For beginners, keeping the total percentage of active ingredients lower (around 25%) can make it easier to formulate a cream with a good texture.