Magnesium Carbonate Hydroxide

What is Magnesium Carbonate Hydroxide?

Magnesium Carbonate Hydroxide is an inorganic compound, a basic hydrated salt formed from magnesium, carbonate, and hydroxide ions, typically with the structure involving multiple magnesium carbonate units and hydroxide. It occurs as a soft, white, odorless microcrystalline powder, often derived from mineral sources or synthesized for purity. In cosmetics, it appears mainly in dry, powder-form products such as face powders, eyeshadows, blushes, setting sprays in powder form, and dry shampoos. It works by absorbing sebum and moisture to provide a matte finish, acting as a mild base to balance acidity in formulations for stability. Its particles help bind other ingredients together, creating cohesive structures in pressed compacts that resist crumbling. This multifunctional role supports smooth application, even coverage, and prolonged wear without altering skin feel dramatically.

Comedogenic Rating 0/5 Low risk of clogging pores
EWG Safety Rating 1 View on EWG →
PubChem View on PubChem →

Roles in Formulation

This ingredient serves the following purposes in cosmetic formulations:

Bulking agent
Increases mass/volume to build structure and improve handling, commonly used to adjust feel, spread, and cost-in-use without acting as a primary active.
PH adjuster
Raises or lowers pH to the target range, supporting ingredient performance, preservative efficacy, stability, and user comfort.
Binding
Provides cohesion by helping ingredients stick together, improving the strength and integrity of pressed powders, tablets, or solid bars.
Buffering agent
Maintains the pH stability of a formulation.
Viscosity controlling agent
Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.

Benefits

Builds volume in formulas for better handling and application.

Helps maintain stable pH levels to support overall product performance.

Binds components for durable pressed powders and improved texture.

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 powder makeup seeking mattifying effects.
People sensitive to inhaling fine powders.
Individuals preferring stable, long-lasting dry cosmetics.
Those with rare magnesium compound allergies.
Those needing better cohesion in compact products.
Users of liquid-only formulations where it's unsuitable.

Safety Notes

  • Rated low hazard by safety assessors for typical cosmetic use.
  • Non-comedogenic, unlikely to clog pores.

Frequently Asked Questions about Magnesium Carbonate Hydroxide

What products contain it?

Common in face powders, eyeshadows, dry shampoos, and pressed cosmetics.

Is it safe for daily use?

Yes, low safety concerns in cosmetic concentrations from reviews.

Does it mattify skin?

It absorbs oils for a smoother, less shiny finish.