Science
Mechanism of Action
This fatty acid salt reduces surface tension at oil-water interfaces, enabling the formation of stable emulsions. In cleansing products, it functions by forming micelles that effectively trap and rinse away dirt and oil.
Research
Clinical Evidence
Medium confidenceN/A
Key findings
- 01 An aqueous solution of 1.5% Ammonium Stearate caused minimal to mild skin erythema in a study of 20 human volunteers.
- 02 Acute dermal toxicity studies demonstrated low potential for systemic toxicity with undiluted Ammonium Stearate in guinea pigs.
Transparency
Dusting Analysis
No data available regarding dusting behavior for this ingredient.
The Formula
Formulation
Stability
Stable in alkaline conditions, with an optimal pH range of 8.0-10.0. It is highly unstable in acidic systems (pH < 7), which can cause emulsion breakage due to decomposition into stearic acid and ammonium ions.
Conflicts
- Acids (causes precipitation/decomposition)
- Strong oxidizing agents
- Multivalent metal ions (e.g., Calcium, Magnesium) which may form insoluble 'scum'
Safety
Safety Profile
The CIR Expert Panel concluded Ammonium Stearate is safe when formulated to be non-irritating. Maximum usage in cosmetics can be up to 15% in leave-on products, with higher concentrations in rinse-off applications.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Ammonium Stearate is a valuable multi-functional ingredient, supporting stable emulsion formation and effective cleansing, with a good safety profile when properly formulated.
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References
Sources