Foaming in Facial Toner Formulation

Question

I am making a facial toner intended for leave-on application, focusing on reducing acne and tightening pores.

After mixing, the formula absorbs quickly and is non-sticky, which is good. However, it creates foam when applied. What could be causing this, and how can it be resolved?

The formula is as follows:

Witch Hazel (alcohol free) plus allantion 78.7%
Ethyl Alcohol 5%
Safe-B3 5%
Encapsulated Salicylic Acid 3.3%
Vitamin B6 3%
L-Carnitine 3%
Zinc PCA 1%
Licorice extract A 1%

The measured pH is 4-5.

Thank you very much.

MySkinRecipes Expert · Accepted Answer

Foaming in Your Facial Toner

It sounds like you've created a great facial toner formula that absorbs well! The foaming you are experiencing during use is likely due to certain ingredients that can reduce the surface tension of the liquid.

Based on your formula, the most probable causes for foaming are:

Witch Hazel (Alcohol Free) plus Allantoin: Witch hazel extract naturally contains compounds that can have mild surfactant properties, leading to foam.
Encapsulated Salicylic Acid: The encapsulation materials used for the salicylic acid might contribute to foaming when dispersed in the toner.
Licorice extract A: Some components in botanical extracts like licorice can also slightly reduce surface tension.

Ingredients like Ethyl Alcohol, Safe-B3 (Vitamin B3), Vitamin B6, L-Carnitine, and Zinc PCA are less likely to be the main culprits for foaming at the concentrations you are using.

How to Reduce Foaming:

Reduce Concentration: You could try slightly lowering the percentage of Witch Hazel or Encapsulated Salicylic Acid. Test this carefully to ensure you maintain the desired effects on acne and pores.
Add an Anti-Foaming Agent: Incorporating a small amount of a cosmetic-grade anti-foaming agent can help. These ingredients break down foam bubbles. You would need to experiment with different types and concentrations.
Gentle Mixing: Ensure your mixing process is not too vigorous, as this can incorporate air and create foam.

Since the toner feels good on the skin, the foaming is mainly a cosmetic issue. You can choose to address it based on your preference or if it affects the user experience.