Hydrated Silica
Silica · Precipitated Silica
What it is
An amorphous form of silicon dioxide (SiO₂) precipitated from solution as microscopic particles. The primary abrasive in most modern toothpastes. Particle size and concentration determine the Relative Dentin Abrasivity (RDA) value.
In this product: Abrasive, physically scrubs surface stains, food debris, and plaque from tooth enamel.
Dose & route, what actually matters
Oral contact, primarily topical. Hydrated silica is insoluble and not systemically absorbed. Minor incidental ingestion is considered safe; the ADA regards toothpastes with RDA ≤250 safe for lifetime daily use.
EUROPEAN UNION
Permitted in EU cosmetics without restriction. No listing in EU Annex II or III.
UNITED STATES
FDA regards hydrated silica as safe for oral care use. No restriction or concern across any regulatory body.
The evidence
ADA Oral Health Topics: ‘The ADA considers any toothpaste with an RDA value of 250 or less safe for daily lifetime use.’ Hydrated silica is the primary abrasive used to achieve target RDA values.
regulatory · 2023 · source
California Prop 65: Not listed.
Where it hides
Editorial analysis of publicly available regulatory and peer-reviewed sources. Not medical advice. We name our evidence and link it, including when an ingredient is fine.