Science
Mechanism of Action
Functioning through its crystalline structure, Guanine reflects light to create a pearlescent effect and a bright white color in cosmetic formulations. This light-scattering property also allows it to reduce the transparency of a product and can be leveraged in makeup applications to effectively mask skin imperfections.
Research
Clinical Evidence
Low confidenceN/A
Transparency
Dusting Analysis
Guanine primarily functions as a cosmetic additive for aesthetic purposes rather than an active ingredient requiring specific efficacious concentrations for skin benefits. Therefore, 'dusting' concerns related to active ingredient efficacy are not applicable.
The Formula
Formulation
Stability
Guanine demonstrates good stability under normal conditions but is incompatible with strong oxidizing agents. While practically insoluble in common solvents like water, alcohol, and ether, it can be dissolved in specific alkaline solutions (e.g., ammonia water, caustic soda, aqueous potassium hydroxide solution) and dilute mineral acids. Its hydrochloride form exhibits solubility in acidified water. Guanine has pKa values at approximately 3.3 (amide), 9.2 (secondary), and 12.3 (primary).
Conflicts
- strong oxidizing agents
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has deferred its evaluation of Guanine, as the U.S. Food and Drug Administration (FDA) has already assessed its safety. The FDA classifies Guanine as a color additive exempt from certification, permitting its safe use in cosmetics, including formulations for the eye area, provided it adheres to FDA specifications. It is also approved for use in externally applied drugs.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Guanine is a safe and well-tolerated cosmetic additive, highly valued for its ability to impart pearlescent effects and opacity, though it does not provide active skin treatment benefits.
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