Science
Mechanism of Action
This amino acid-derived ingredient functions through a dual mechanism. As a surfactant, its amphiphilic structure, featuring a hydrophobic stearic acid part and a hydrophilic glutamic acid part, efficiently reduces water's surface tension. This enables superior mixing with oils and impurities for gentle yet thorough cleansing without stripping the skin's natural lipids. Concurrently, as an emulsifier, it is crucial for stabilizing cosmetic formulations, ensuring uniform dispersion of oil and water phases for a consistent, smooth product texture. Beyond these primary roles, it actively contributes to skin hydration, helps fortify the natural moisture barrier, and minimizes transepidermal water loss. Its ability to form lamellar liquid crystalline structures enhances skin feel, resulting in a silky, rapidly absorbed finish, and also provides skin-softening benefits and inherent antimicrobial properties to protect product integrity.
Research
Clinical Evidence
Medium confidenceN/A
Key findings
- 01 Usage levels in cosmetics typically range from 0.03% to 2.0%, with concentrations exceeding 1.0% often found in leave-on products.
- 02 The ingredient offers good viscosity benefits at concentrations as low as 0.25%, with maximum reported usage for this purpose up to 2.0%.
- 03 While generally mild, one case reported irritant contact dermatitis to a 1.0% leave-on product, though potential contributions from other ingredients were noted.
- 04 Separately, a case of allergic contact dermatitis revealed positive patch test reactions (++) to Sodium Stearoyl Glutamate at a 1.0% aqueous concentration.
Transparency
Dusting Analysis
Sodium Stearoyl Glutamate is effective at low concentrations, such as 0.25% for viscosity, and is typically used from 0.03% upwards. This indicates that its inclusion at functional percentages is common, making dusting less likely above its minimum effective usage level.
The Formula
Formulation
Stability
This ingredient maintains stability within the skin-relevant pH range of 4.5 to 5.5 and demonstrates good tolerance to salts. It is versatile, suitable for both oil-in-water (O/W) and water-in-oil (W/O) emulsions, and can be efficiently incorporated into either the oil or aqueous phase during both cold and hot manufacturing processes, exhibiting efficacy even at low concentrations.
Conflicts
- Cationic surfactants
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has determined Sodium Stearoyl Glutamate to be safe for use in cosmetics within established guidelines, up to a maximum concentration of 2.0%. While frequently described as mild and non-irritating, there are documented reports. These include an instance of irritant contact dermatitis from a 1.0% leave-on product (with possible confounding factors from other ingredients), and a separate case of allergic contact dermatitis confirmed by positive patch tests to a 1.0% aqueous solution. This highlights its potential as an 'amino acid alkyl amide sensitizer' for certain susceptible individuals.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Sodium Stearoyl Glutamate is a valuable, multifunctional ingredient that gently cleanses, stabilizes formulations, and enhances skin barrier function and hydration, making it suitable for a wide range of skin types despite rare documented reports of sensitization.
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References
Sources