Adjusting Ingredient Percentages in Formulations

When you add an ingredient to a formulation, you must reduce the percentage of other ingredients to keep the total percentage at 100%. The choice of which ingredient(s) to reduce depends on the role of each ingredient in the formula.

1. Adding Allantoin to the Gel Formula:

   • Your assumption is correct. In your example formula (Vitamin B3 2% + NAG 4% + Propolymer 1% + Preservative 1% + Water 92%), if you add Allantoin 2%, the total percentage becomes 102%. To bring it back to 100%, you need to reduce other ingredients by a total of 2%.
   • Reducing the main base ingredient, which is water (92%), is the most common and often the simplest way to accommodate a small addition of an active ingredient like Allantoin. So, reducing water from 92% to 90% is a valid approach, resulting in a new formula totaling 100% (Vitamin B3 2% + NAG 4% + Propolymer 1% + Preservative 1% + Allantoin 2% + Water 90%).

2. Adding Vitamin B3 and NAG to the Pitera Formula:

   • Your Pitera formula is: Galactomyces Ferment Filtrate 79% + Distilled Water 15% + Rose Hip Oil 5% + Light Cream Maker™ 1%. Total = 100%.
   • If you want to add Vitamin B3 4% and NAG 4%, you are adding a total of 8% (4% + 4%). This means you need to reduce other ingredients in the formula by a total of 8% to maintain the 100% total.
   • As mentioned in the provided response, you would typically reduce either the water or the Galactomyces Ferment Filtrate, or a combination of both.
     • Reducing Water: You could reduce water from 15% down to 7% (15% - 8% = 7%). The new formula would be: Galactomyces Ferment Filtrate 79% + Distilled Water 7% + Rose Hip Oil 5% + Light Cream Maker™ 1% + Vitamin B3 4% + NAG 4%. Total = 100%. However, reducing water significantly might affect the solubility of water-soluble ingredients or the overall texture.
     • Reducing Galactomyces Ferment Filtrate: You could reduce the Galactomyces Ferment Filtrate from 79% down to 71% (79% - 8% = 71%). The new formula would be: Galactomyces Ferment Filtrate 71% + Distilled Water 15% + Rose Hip Oil 5% + Light Cream Maker™ 1% + Vitamin B3 4% + NAG 4%. Total = 100%. This maintains the water content but reduces the concentration of the original main ingredient.
     • Reducing Other Ingredients: Reducing the Rose Hip Oil (5%) or the Light Cream Maker™ (1%) by a large amount (like 8%) is generally not advisable unless the new ingredients or the desired final product characteristics allow for it. Rose Hip Oil is an oil phase component, and Light Cream Maker™ is a thickener/emulsifier; these have specific roles and concentration ranges needed for the formula's stability and texture.
   • The best approach depends on your formulation goals and the compatibility of the ingredients. Reducing water is often the first consideration for water-soluble actives, but you must ensure the new actives are soluble in the reduced water amount. Reducing the main base ingredient (like the Galactomyces Ferment Filtrate in this case) is also an option, but it changes the concentration of that specific ingredient.

3. General Principles for Adjusting Percentages:

   • Maintain 100% Total: Always ensure the sum of all ingredient percentages equals 100%.
   • Consider Ingredient Function: Understand the role of each ingredient:
     • Actives: These are the ingredients providing the main benefit (e.g., Vitamin B3, NAG, Allantoin, Galactomyces Ferment Filtrate). You are usually adding or changing these.
     • Base/Vehicle: These form the bulk of the product (e.g., Water, Oils). They dissolve/disperse other ingredients and contribute to the product's feel and spreadability. These are often the easiest to adjust for small changes in actives.
     • Thickeners/Gelling Agents/Emulsifiers: These provide structure, viscosity, and stability (e.g., Propolymer, Light Cream Maker™). They are used within specific concentration ranges and should only be adjusted carefully if the formula characteristics change.
     • Preservatives: These prevent microbial growth. They are used at effective minimum concentrations and should generally not be reduced unless the new ingredients have preservative properties or the total formula volume changes significantly.
     • Other Additives: Fragrance, colorants, pH adjusters, etc., are usually used at low percentages and adjusted last if needed.
   • Prioritize Functional Ingredients: Avoid significantly reducing ingredients critical for the formula's stability, texture, or preservation unless you are reformulating based on the properties of the new ingredients.
   • Start with the Base: For small additions of actives, reducing the primary base ingredient (like water or a main oil) is usually the most straightforward approach.
   • Consider Solubility and Compatibility: Ensure the new ingredients are soluble or dispersible in the adjusted base and are compatible with the other ingredients.
   • Testing: After adjusting, it is crucial to test the new formulation for stability, efficacy, texture, and safety.

In summary, when adding ingredients, you must reduce others to keep the total at 100%. Reducing the base (like water or oil) is a common strategy, but always consider the function of each ingredient and how changes might affect the overall formula. For significant changes or complex formulas, careful calculation and testing are essential.