Formulation questions for BHA serum/gel (gelling, preservation, ingredients)
Asked by: glory_fleur
On: November 20, 2014
Product Type:
Cosmetics
Question
I am developing a BHA formulation for normal skin with clogged pores. I have a few questions regarding the formulation:
- I plan to use Tea Tree Oil at 0.5%. Is this concentration suitable, and what type of container should I use?
- Can I use Pro Polymer instead of Hydroxyethyl Cellulose to create a gel texture? What are the implications for texture, mixing, and compatibility with heat-sensitive ingredients like Calendula extract, Vitamin B5, and Allantoin? What is the recommended starting percentage for Pro Polymer, and can it be increased to 2%?
- Is it necessary to include a dedicated preservative in this formula, given that Salicylic Acid has some antimicrobial properties?
Answer
Regarding your BHA formulation for normal skin with clogged pores:
- Tea Tree Oil: At 0.5%, the container type is not a major concern; any container is fine. However, Tea Tree Oil can be irritating, so it's important not to exceed 0.5% in the formula.
- Alternative to Hydroxyethyl Cellulose: Yes, you can use Pro Polymer as an alternative, especially with standard Salicylic Acid. Using Pro Polymer might result in a cloudy texture, but it's easier to mix as it doesn't require heat. This is beneficial for heat-sensitive ingredients like Calendula extract, Vitamin B5, and Allantoin, which should be added after any heating step if heat is used. For Pro Polymer, it's recommended to start with 1-1.5% and increase to 2% if a thicker texture is desired, adding it gradually while mixing.
- Preservative: While Salicylic Acid has some antimicrobial properties and can act as a preservative, a dedicated preservative is generally more effective. If you are mixing the formula at home with strict cleanliness, it might be possible to omit a dedicated preservative. However, for greater certainty regarding microbial stability, especially when not able to perform efficacy testing like commercial manufacturers, it is recommended to include a dedicated preservative at the appropriate concentration.