Common Name(s): Aluminum behenate,aluminum metallic soap,colour cosmetic glidant powder

CAS Number: N/a

DESCRIPTION

What It Does: Aluminum behenate provides silky powder flow and excellent skin adhesion in colour cosmetics and face powders, contributes mild aluminum astringency for improved cosmetic wear, forms a water-resistant hydrophobic film on skin that extends make-up longevity through perspiration, and binds compressed powder tablets together in pressed-powder formulations through the wax-like fatty acid crystal cohesion.

Why It's Used: Formulators choose aluminum behenate for pressed and loose colour cosmetic powder formulations because metallic soaps provide a unique functional triad that no single non-metallic ingredient can replicate: (1) the fatty acid anion provides lubricity and silky skin-glide from the waxy hydrocarbon surface; (2) the aluminum cation provides astringency and water resistance from the ionic metal-skin protein interaction; (3) the crystal plate morphology provides particle-particle cohesion for compressed powder tablet integrity. this three-in-one functionality at 1–20% concentration makes metallic soaps irreplaceable in commercial colour cosmetic formulation despite the availability of individually superior alternatives for each function.

How It Works: Aluminum behenate works through its metallic soap crystal architecture's dual surface chemistry: the aluminum divalent (or trivalent for aluminium) ion bridges two or three fatty acid carboxylate anions forming a layered crystalline structure. individual crystals are plate-like with the metal-carboxylate ionic plane buried inside and the hydrocarbon chain ends forming the outer surface. the waxy hydrocarbon outer surface has a water contact angle of 90–110° (hydrophobic) and low surface energy (~25 mn/m) providing inter-crystal lubricity and smooth skin-glide. the ionic inner structure provides crystal cohesion for pressed powder. on skin contact, the aluminum ions at crystal edges interact with skin surface carboxylate and amine groups from mild ionic bonding — providing the adhesion that keeps face powder on skin through the wear period. the water-resistance arises from the hydrophobic crystal surface that prevents aqueous sweat from penetrating and disrupting the powder layer.

Typically Found In: Face powders,colour cosmetics,pressed foundations

TECHNICAL DETAILS

Primary Category: Functional ingredient – emollient

Secondary Functions: Barrier sealing,softening

Application Areas:

Typical Concentration Range: 1%–20%

SOURCING & ETHICS

Vegan Status: Conditional

Halal Status: Yes

Source Notes: Plant-derived, synthetic or animal-derived. verify source.

SKIN COMPATIBILITY

Irritancy Rating: 1/5 – very low

Comedogenicity Rating: 1/5 – low; formulation-dependent

Sensitivity Concerns: Non-irritating.

Safe for Sensitive Skin: Yes

SAFETY & COMPATIBILITY

Safety Profile: Excellent safety profile. ewg score: 1.

Works Well With: Humectants,ceramides,actives as carrier

Avoid Combining With: No significant incompatibilities

SCIENTIFIC NOTE

Metallic soap crystal morphology effect on skin feel: aluminum stearate forms small (~5 μm) lamellar plate crystals with high aspect ratio (width/thickness ~10). under applied finger pressure, these plates slide over each other along the cleavage plane (inter-plate lubricity) providing the characteristic silky glide. larger crystallites provide more glide; smaller provide better adhesion from higher surface area-to-volume ratio. formulators control metallic soap particle size through precipitation conditions during manufacture to tune the glide-adhesion balance for specific cosmetic product requirements.

Last Verified: Cosing database,aluminum behenate metallic soap colour cosmetic review

Primary Sources: 2026-03-12