Comparing Coco Wash and Coco Betaine for Shampoo Formulation and Viscosity Issues with pH Adjustment

Subject: Clear Clean in shampoo not thickening after adding Citric acid

Hello,

Thank you for your questions regarding your shampoo formulation.

Regarding Question 1: The issue of your shampoo losing viscosity and becoming liquid after adding Citric Acid to lower the pH is likely related to the sensitivity of the thickener/solubilizer (Clear Clean) or the overall surfactant system to changes in pH. Different thickeners and surfactant combinations have specific pH ranges where they provide optimal viscosity. In your formula, the combination of Decyl Glucoside, Mild Wash (Sodium Lauroamphoacetate), and Clear Clean appears to lose its thickening ability when the pH is adjusted downwards to 5-5.5 with Citric Acid. It's possible that Clear Clean's effectiveness is significantly reduced in a more acidic environment, especially in this specific surfactant blend. While Clear Clean is mentioned to cause cloudiness with Glucoside, its pH sensitivity regarding thickening is a separate factor. Using a more precise pH meter (like a digital pH meter) instead of litmus paper would provide more accurate readings and better control during pH adjustment, but the fundamental issue here seems to be the ingredient compatibility with the target pH.

Regarding Question 2: You are correct that Coco Wash (PEG-7 Glyceryl Cocoate) is chemically different from Coco Betaine (Cocamidopropyl Betaine). They belong to different classes of ingredients and have different primary functions in formulations. Coco Betaine is an amphoteric surfactant commonly used for foaming and viscosity building in cleansers, while PEG-7 Glyceryl Cocoate is a non-ionic solubilizer and refatting agent, often used to improve the feel of the skin after washing or to solubilize oils/fragrances. As the staff mentioned, PEG-7 Glyceryl Cocoate is generally more suitable for products like makeup removers rather than as a primary or secondary surfactant in a shampoo intended for significant foaming and cleansing. Given your allergy to Coco Betaine, it is wise to avoid it. The staff has offered to perform testing and suggest an alternative formula that avoids Coco Betaine. We recommend waiting for their specific recommendation, as they can provide a tested formula suitable for your needs and allergy concerns.

We hope this explanation is helpful.