Science
Mechanism of Action
Umber, specifically synthetic iron oxides, primarily functions by imparting various shades to cosmetic products. Beyond its pigmentary role, it acts as a physical barrier on the skin's surface, reflecting and scattering high-energy visible (HEV) light, particularly within the 400-490 nm blue light spectrum. This protective action mitigates the effects of blue light on melanocytes, thereby aiding in the prevention and management of hyperpigmentation, including melasma. Certain nanoscale iron oxides may also contribute antioxidant benefits by reducing oxidative stress.
Research
Clinical Evidence
Medium confidenceN/A
Transparency
Dusting Analysis
No data available regarding dusting properties of Umber in the provided research.
The Formula
Formulation
Stability
Iron oxides exhibit excellent stability against light and maintain integrity across a broad pH range of 3-11. However, yellow and black iron oxides are susceptible to color shifts at high temperatures (125-150°C), with yellow potentially losing water of hydration and black becoming redder.
Synergies
- Zinc oxide and Titanium dioxide: Enhances broad-spectrum and blue light protection in multi-ingredient sunscreens and tinted formulations.
Conflicts
- High temperatures (125-150°C): May cause color shifts in yellow and black iron oxides.
- Iron or mild steel containers: Magnetic properties of iron oxides can lead to coating, necessitating careful material selection for manufacturing equipment.
Safety
Safety Profile
The Cosmetic Ingredient Review (CIR) Expert Panel has deferred evaluation of iron oxides, as their safety is overseen by the U.S. Food and Drug Administration (FDA). The FDA recognizes iron oxides as a color additive exempt from certification, deeming them safe for general cosmetic use, including lip and eye products, provided specific purity standards are met. They are also listed as Generally Recognized As Safe (GRAS) for indirect food additive applications. In the EU, iron oxides (CI 77491, CI 77492, CI 77499) are permitted as coloring agents without restriction under Annex IV, Part I of the Cosmetics Regulation, contingent on purity compliance, which includes strict limits on heavy metal contamination.
Your Skin
Skin Compatibility
Our Assessment
Verdict
Umber is a valuable ingredient, not only for its coloring properties but also for its proven efficacy in blue light protection and low irritancy, making it suitable for a wide range of precision skincare applications.
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References
Sources