Science
Mechanism of Action
Magnesium Hydroxide functions as a critical formula regulator by neutralizing acids to achieve optimal pH levels, such as adjusting cleansers to a pH of 6.5–8.0 and buffering exfoliating acids like AHAs to mitigate irritation. Its mild basicity helps inhibit the proliferation of Cutibacterium acnes, reducing skin inflammation and neutralizing odor-causing bacteria. Possessing strong adsorptive qualities, it effectively soaks up excess sebum and sweat, thereby controlling shine and maintaining skin dryness. Additionally, it acts as a textural agent, enhancing formulation consistency as a filler and texturizer, and offers calming properties that soothe discomfort.
Research
Clinical Evidence
High confidenceOptimal percentage varies by application: 0.2-1.5% for pH adjustment, 1-3% for mild cleansing/soothing, 5-15% for deodorizing, and 10-30% for oil absorption.
Key findings
- 01 Observed clinical efficacy is based on typical usage levels in cosmetics, demonstrating regulating functions at ≤1%, deodorizing at 5-15%, and significant oil absorption at 10-30% in powder masks. It also provides mild cleansing and soothing effects at 1-3%.
Transparency
Dusting Analysis
The Formula
Formulation
Stability
Magnesium Hydroxide is practically insoluble in water but dispersible, and soluble in dilute acids. Its aqueous slurry typically registers a pH of 10.5-11.0. It effectively neutralizes acidic formulations (pH < 7.0) and can precisely adjust product pH, for instance, to 6.5-8.0 in cleansers. Due to its slow reaction with acids, it does not drastically elevate pH above 7.0 in already neutral or alkaline products. Careful pH management is essential, as maintaining an excessively high in-use pH (e.g., ≥10) can compromise the skin's acid mantle and increase irritation risk. High-purity raw materials are recommended.
Conflicts
- Over-neutralization or maintaining an in-use pH of ≥10 can disrupt the skin's acid mantle and increase irritation risk.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has deemed Magnesium Hydroxide safe as used, provided products are formulated to be non-irritating. While specific concentrations in hair straighteners and depilatories advise minimizing skin contact, there are no special concentration limits under general cosmetic regulations. High-purity raw materials are critical, with heavy metal content controlled below 10ppm. The FDA has affirmed Magnesium Hydroxide as Generally Recognized as Safe (GRAS) for food and approved its use in OTC antacid drug products, further validating its safety profile. In vitro tests indicate it is non-irritating and non-corrosive.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Magnesium Hydroxide is a valuable multi-functional ingredient, adept at pH regulation, sebum control, and mild odor neutralization, making it suitable for a wide range of skincare applications, particularly for oily and sensitive skin.
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