Aluminum Tristearate

What is Aluminum Tristearate?

Aluminum tristearate is a synthetic salt formed from aluminum hydroxide and stearic acid, a saturated fatty acid typically sourced from plant or animal fats. Appearing as a fine, white, odorless powder insoluble in water, it belongs to the class of aluminum soaps widely used in cosmetic formulations such as pressed powders, foundations, creams, lotions, and anhydrous products. In these applications, it functions by creating a structured network that absorbs excess moisture to inhibit clumping, reinforces the interface between oil and water phases to maintain emulsion integrity, and modifies the rheological properties to achieve optimal spreadability and suspension of other ingredients. This versatility makes it valuable in both decorative and skincare products where texture and stability are essential for performance and shelf life.

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.
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

Enhances powder flow and uniformity by absorbing moisture to prevent clumping.

Strengthens emulsions against separation for longer-lasting product stability.

Adjusts product thickness for smoother application and better ingredient dispersion.

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 clump-free texture.
Those with rare aluminum contact sensitivities.
Individuals applying emulsion-based creams or lotions for consistent performance.
Individuals preferring aluminum-free formulations on personal choice.
People preferring stable makeup foundations that maintain integrity over time.
Users sensitive to fatty acid derivatives from specific sources.

Safety Notes

  • Rated low hazard by major cosmetic safety assessors.
  • Minimal skin penetration due to its insoluble, large-particle nature.

Frequently Asked Questions about Aluminum Tristearate

What is aluminum tristearate used for in cosmetics?

It acts as an anticaking agent in powders, emulsion stabilizer in creams, and viscosity controller for better texture.

Is aluminum tristearate safe for skin?

Yes, it carries a low safety rating from authoritative cosmetic databases with no significant concerns at typical levels.

Does it affect pore clogging?

No, it has a comedogenic rating of 0, suitable for acne-prone skin formulations.