Science
Mechanism of Action
As a blended salt of sodium carbonate and bicarbonate, Sodium Sesquicarbonate moderates the pH of aqueous solutions, typically resulting in a mildly alkaline environment (e.g., pH 9.9 at 10% concentration or 10.1 for a 0.1M solution). Its bicarbonate component contributes to buffering capacity. Beyond pH adjustment, it acts as a cleansing agent and softens water by precipitating calcium and magnesium ions.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
Sodium Sesquicarbonate can exist as a fine dust (known as Trona dust), which, due to its alkalinity (pH 10.5), has been noted to potentially irritate mucous membranes and skin upon exposure.
The Formula
Formulation
Stability
Aqueous solutions are mildly alkaline (pH ~9.9-10.1), while its crystalline form is stable in air. It is cold water soluble, distinguishing it from Sodium Carbonate, and is particularly useful in formulations requiring additional buffering.
Conflicts
- acids
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel deemed Sodium Sesquicarbonate 'safe as presently used' in cosmetics, a conclusion reaffirmed in 2023. While historically used up to 50%, the maximum reported concentration in 'Other Skin Care Preparations' is 30.8%. It holds a Generally Recognized As Safe (GRAS) designation by the FDA for specific food uses. However, there are noted concerns regarding potential irritation, especially with prolonged exposure, on damaged skin, or when moisture is present.
Your Skin
Skin Compatibility
Our Assessment
Verdict
While effective as a pH adjuster and cleansing agent and deemed safe for cosmetic use up to 30.8%, its mild alkalinity and potential for irritation at higher concentrations or with prolonged exposure suggest careful consideration for precision skincare formulations, especially for sensitive skin.
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