Facial Spray Formulation: Phenoxyethanol, Natural Preservatives, and Irritation

Question

I have developed a facial spray formulation and have some questions regarding the ingredients and preservatives:

My formula consists of:

Water 96%
Disodium EDTA 0.2%
Calendula Extract 3%
Phenoxyethanol 0.8%

Is this formula acceptable?
Given that this is a spray applied to the entire face, is there a risk of irritation from Phenoxyethanol, even the Extra Pure grade?
Can natural preservatives be used as an alternative?
Are natural preservatives effective enough to control microbial growth in jar-type products?
When combining multiple preservatives, should they be used at their full recommended rates (e.g., Phenoxyethanol 1% + natural preservative 1% = 2%) or at reduced rates (e.g., Phenoxyethanol 0.5% + natural preservative 0.5% = 1%)?

MySkinRecipes Expert · Accepted Answer

Facial Spray Formulation Review

Let's review your proposed facial spray formulation and address your questions about preservatives.

Your formula consists of:

Water 96%
Disodium EDTA 0.2%
Calendula Extract 3%
Phenoxyethanol 0.8%

The percentages add up to 100%, and the components are commonly used in cosmetic formulations. The usage rates for Disodium EDTA (0.2%) and Calendula Extract (3%) are within typical recommended ranges. Phenoxyethanol at 0.8% is also within the general recommended range (0.5-1.0%).

Regarding your questions:

Is the formula OK? The formula is a standard water-based spray formulation. The combination of ingredients is reasonable for a hydrating and potentially soothing facial spray, assuming the raw materials are suitable for cosmetic use.
Can Phenoxyethanol cause irritation when sprayed on the face? Yes, Phenoxyethanol, even the Extra Pure grade, can potentially cause skin irritation, especially for sensitive skin or when used in a spray form that might be inhaled or come into contact with eyes. While the maximum allowed concentration in cosmetics is typically 1%, using 0.8% is close to this limit. The risk of irritation exists, although individual sensitivity varies.
Can natural preservatives be used instead? Yes, natural preservatives can be used as alternatives to Phenoxyethanol. Options like NaturePreserve™ Ultra (Gluconolactone & Sodium Benzoate) or NaturePreserve™ LB2 are available.
Are natural preservatives effective enough for jar products? Natural preservatives like NaturePreserve™ Ultra and NaturePreserve™ LB2 can be effective in controlling microbial growth in various product types, including jar products which have higher risk of contamination. However, achieving sufficient preservation depends on the specific formula's composition and the chosen preservative's usage rate. For jar products with more exposure to germs, a higher concentration within the recommended range (e.g., 1.5-2.0% for NaturePreserve™ Ultra) might be necessary.
Combining preservatives: full rate or reduced rate? When combining multiple preservatives, it's not simply a matter of adding their maximum individual usage rates or halving them. The effectiveness of a preservative blend depends on the specific combination and the overall formula composition (e.g., presence of ingredients that support or hinder microbial growth). Large manufacturers typically perform challenge testing on the final formula to determine the minimum effective and safe concentration of the preservative system. You can combine preservatives, and the total concentration might exceed the limit of a single preservative if the combination is proven effective and safe for the specific product through testing.