Formula Thinning with Glycerin and Salt in Surfactant Base

Hello,

Thank you for reaching out. It's interesting that your formula thins when you add both glycerin and salt, but thickens when you use salt alone.

Here's a possible explanation:
Salt (like Sodium Chloride) is commonly used to thicken surfactant-based formulas (like shampoos and body washes) by influencing the structure of the surfactant micelles. However, this thickening effect is very sensitive to the presence of other ingredients and their concentrations.

Glycerin is a humectant and a solvent. While beneficial for skin/hair hydration, it can, especially at higher concentrations, interfere with the way salt interacts with the surfactant micelles. This interference can disrupt the thickening mechanism, causing the formula to become less viscous or even thin out.

To give you precise advice on how to fix this, we really need to know the full list of ingredients and their percentages in your formula, as the interaction between glycerin, salt, and the surfactants you are using is key.

However, based on your description, here are some general points to consider:

• Glycerin Concentration: High levels of glycerin are more likely to cause this thinning effect. You might need to reduce the amount of glycerin if possible.
• Surfactant System: The specific types and combinations of surfactants you use play a big role in how they respond to salt and glycerin.
• Alternative Thickeners: If you need to keep the glycerin level high, you might need to use a different type of thickener that is not as sensitive to glycerin, such as polymer thickeners (e.g., cellulose derivatives, carbomers, acrylates copolymers).

Please provide your full formula (ingredients and percentages) so we can offer more specific recommendations.