Sodium Metasilicate

What is Sodium Metasilicate?

Sodium metasilicate is an inorganic compound, specifically the sodium salt of metasilicic acid with the formula Na₂SiO₃, often hydrated. It dissolves readily in water to form strongly alkaline solutions due to its basic nature. In cosmetic formulations, particularly rinse-off products like cleansers and shampoos, it serves functional roles rather than direct skin benefits. It acts as a buffering agent to stabilize pH levels, preventing fluctuations that could destabilize other ingredients. As a chelating agent, it binds metal ions from water or raw materials, reducing their interference with product efficacy and appearance. Additionally, it functions as a corrosion inhibitor, safeguarding metal packaging from degradation, which helps maintain product integrity over time without leaching contaminants.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 2 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Chelating agent
Binds to metal ions to prevent them from affecting product stability or skin.
Corrosion inhibitor
Reduces corrosion reactions on metal surfaces in packaging or applicators, helping prevent rust, off-odors, and metal-related discoloration over time.
Anticorrosive
Protects metal components and packaging by reducing corrosion, helping maintain product integrity and preventing discoloration or contamination from metal surfaces.
Buffering agent
Maintains the pH stability of a formulation.

Benefits

Stabilizes product pH for consistent performance.

Binds metal ions to enhance formulation clarity and stability.

Protects packaging from corrosion, preserving product quality.

Who It's For

A quick guide for who this ingredient may suit (and who should be cautious).

Who May Benefit Who Should Avoid
Users of rinse-off cleansers requiring pH stability.
Those with highly sensitive or compromised skin barriers.
Individuals with products in metal containers prone to rust.
Individuals prone to irritation from alkaline substances.
People seeking stable, long-lasting formulations without metal discoloration.
Users applying leave-on products with high pH ingredients.

Safety Notes

  • Typically used in low concentrations in rinse-off products to minimize contact.
  • Alkaline nature requires thorough rinsing to avoid potential irritation.

Frequently Asked Questions about Sodium Metasilicate

What is sodium metasilicate used for in skincare?

It buffers pH, chelates metals, and inhibits corrosion in rinse-off products like cleansers.

Is sodium metasilicate irritating to skin?

Potential for irritation exists due to alkalinity, but low risk in diluted, rinsed formulations.

Is it safe in cosmetics?

Yes, when used within guidelines in rinse-off products by regulatory standards.