Preservative for Clear Oil Gel with Low Water Content

Question

I am developing a Clear Oil Gel formulation that contains only 4% water. Is a preservative necessary for this formula? If so, what is the recommended method and timing for adding the preservative (e.g., Phenoxyethanol) to ensure its effectiveness and stability within the gel?

MySkinRecipes Expert · Accepted Answer

Preservative for Clear Oil Gel Formulation

Yes, a preservative is needed for your Clear Oil Gel formulation. Even though the water content is only 4%, the presence of water makes the product susceptible to microbial growth, especially when stored in environments like a bathroom which can be humid.

While some preservatives like Phenoxyethanol have temperature limitations for addition, the general method for this type of formulation is to add the preservative at the final step, after the main heating phase (70-80°C) is complete and the gel has formed. Add the preservative while the gel is still warm (but cooling down) at a recommended rate of 0.5-1.0%. Mix thoroughly to ensure it is evenly distributed throughout the gel.

Adding the preservative at this stage ensures its effectiveness without being degraded by high temperatures, while the warmth of the gel allows for easier incorporation compared to adding it when fully cooled and thickened.