Aluminum Stearate

What is Aluminum Stearate?

Aluminum stearate forms through the reaction of stearic acid—a saturated fatty acid from plant or animal sources—with aluminum compounds, yielding a hydrophobic white powder insoluble in water but dispersible in oils. Primarily featured in makeup powders, pressed powders, anhydrous sticks, and oil-in-water emulsions like creams and lotions, it functions by adsorbing onto particle surfaces to inhibit clumping and enhance powder flowability. In emulsions, it reinforces the oil-water interface, averting separation and boosting shelf stability. As a viscosity controller, it thickens formulations for optimal spreadability and suspension of actives. Its mild opacifying effect aids in color uniformity without staining skin, making it versatile across decorative and personal care products for consistent performance and sensory appeal.

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:

Anticaking agent

Prevents powders from clumping by reducing moisture pickup and improving flow, keeping loose and pressed powders uniform during storage and use.

Colorant

Provides or corrects color using dyes or pigments, helping achieve a consistent shade and visual appearance across batches and throughout wear.

Emulsion stabilizer

Improves emulsion robustness by preventing droplet coalescence and phase separation, often by thickening, structuring, or strengthening the interfacial layer.

Viscosity controlling agent

Adjusts thickness to the desired level for stability and usability, improving dispensing, suspension, and texture across many formulation types.

Benefits

Supports smooth application by preventing powder clumping and improving flow in makeup.

Strengthens emulsion stability to maintain product integrity over time.

Optimizes texture and thickness for better user experience in creams and lotions.

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 loose or pressed powders seeking uniform texture.	People with known sensitivity to aluminum compounds.
Individuals with products containing emulsions for enhanced durability.	Individuals preferring aluminum-free formulations.
Those preferring non-comedogenic ingredients in oil-based formulas.	Users concerned about trace metal content despite low absorption.

Safety Notes

Recognized as safe for cosmetic use with low hazard ratings from assessments.
Minimal skin penetration due to insolubility, reducing systemic exposure.

Frequently Asked Questions about Aluminum Stearate

What is aluminum stearate made from?

It is the aluminum salt of stearic acid, derived from fatty acids in vegetable or animal origins, processed into a fine powder.

Is aluminum stearate safe for skin?

Safety evaluations deem it safe as used in cosmetics, with low irritation potential and minimal absorption.

Does it cause breakouts?

It carries a comedogenic rating of 0, indicating low likelihood of pore clogging.