Adjusting Physical Sunscreen Formula for Spray Application

Question

Following up on the previous discussion about adjusting my physical sunscreen formula (containing Zinc Oxide, Titanium Dioxide, Cyclomethicone, CreamMaker EG, Glycerin, and 7% Propylene Glycol) for better spreadability, I would like to ask: Which formula can be developed into a spray? What ingredients need to be added or reduced to achieve a sprayable consistency? Do you have any existing sprayable physical sunscreen formulas you could share?

MySkinRecipes Expert · Accepted Answer

Physical Sunscreen Formulation Adjustment

It's great that you were able to improve the spreadability of your physical sunscreen formula by adding Propylene Glycol.

Regarding your question about the safety of using 7% Propylene Glycol in a leave-on product daily, based on the information provided, this concentration is considered safe. Propylene Glycol is widely accepted and can be used at concentrations up to 20% without irritation, and up to 50% according to regulatory guidelines. Your use of 7% is well within these safe limits.

Propylene Glycol, similar to Glycerin, acts as a humectant and solvent, which can contribute to a smoother feel and better spreadability in formulations.

The staff also suggested exploring emollients like LipidSoft C1215 as an alternative to Propylene Glycol, noting that it could potentially offer even better skin feel and spreadability.

Your formula includes key physical sunscreen ingredients like Zinc Oxide and Titanium Dioxide, along with Cyclomethicone, CreamMaker EG as an emulsifier/thickener, and Glycerin. The chemical sunscreen you referenced contained ingredients such as Ethylhexyl Methoxycinnamate and Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (similar to Bisoctrizole).

Your adjustment with 7% Propylene Glycol is a reasonable approach to address the texture issue while remaining within safe usage levels.