Ingredient Properties and Compatibility in Acidic Serum Formulation
Asked by: sivacoupe
On: June 14, 2014
Product Type:
Cosmetics
Question
I have a few questions regarding ingredient properties and compatibility in an acidic serum formulation (pH 3.1-3.3):
- What are the differences in viscosity and stickiness between Butylene Glycol and Propylene Glycol?
- Will Lemon Peel Bioferment remain active and stable when used in a formula with a pH of 3.1-3.3?
- Can essential oils be added for fragrance to a serum with a pH between 3.1-3.3, and will their stability be affected by this low pH?
Answer
Here are the answers to your questions based on the information provided:
- Butylene Glycol vs. Propylene Glycol Viscosity and Stickiness:
- Butylene glycol is more viscous (thicker) than propylene glycol. At 25°C, Butylene Glycol has a viscosity of 104 mPa.s, while Propylene Glycol has a viscosity of 48.6 mPa.s.
- However, higher viscosity does not necessarily mean more stickiness. Butylene glycol does not feel stickier than propylene glycol.
- Lemon Peel Bioferment Activity at pH 3.1-3.3:
- Lemon Peel Bioferment is recommended for use in formulations with a pH range of 3.5-7.
- Using it in a formula with a pH of 3.1-3.3 will still allow it to be active, but its stability and shelf life will be reduced. For example, its shelf life might decrease from the specified 18 months to around 12 months, meaning it will degrade faster.
- Essential Oils in Acidic Serum (pH 3.1-3.3):
- Essential oils do not have a pH and are not affected by the pH of the water phase in a formulation because they are not water-soluble.
- Only ingredients that are soluble in water (whether powder or liquid) are affected by the pH of the formulation's water phase.
- Therefore, adding essential oils for fragrance to a serum with a pH between 3.1-3.3 is possible, and the essential oils' stability is generally not dependent on the pH of the water phase.