STEARALKONIUM CHLORIDE (Stearalkonium chloride) – function in cosmetics

A quaternary ammonium salt used as an antistatic agent and preservative, regulated in Annexes III and V.

What it is

Stearalkonium chloride is benzyldimethylstearylammonium chloride, a cationic quaternary ammonium salt with a C18 alkyl chain related to benzalkonium chloride. CosIng lists it as an antistatic agent, preservative and cleansing surfactant. In the EU it is covered by the benzalkonium entries in Annex III (substances subject to restrictions) and Annex V (allowed preservatives).

Where it is used

Found mainly in hair conditioners, hair masks and other rinse-off hair products.

Limits of interpretation

The INCI list shows which ingredients are present, not how much of each. Above 1%, ingredients are listed in descending order of weight; below 1% the order is free.

See the EU regulation section for the applicable limits and warnings, which depend on the product type and purpose; according to the entries, the limits are expressed as benzalkonium chloride.

Functions

Antistatic

Preventing and/or reducing static electricity by neutralising electrical charge on surfaces.

Preservative

Exclusively or mainly intended to inhibit the development of micro-organisms in the cosmetic product. All authorised preservatives are substances in the positive list of Annex V to the Cosmetics Regulation 1223/2009.

Surfactant – cleansing

Wetting body surfaces, emulsifying or solubilizing oils, and suspending soil (generally, such ingredients contribute to the foaming and lathering properties of cleansing products).

EU regulation

EU · Annex III, entry 65Benzalkonium chloride, bromide and saccharinate (9)

Product type: Rinse-off hair (head) products
Maximum concentration: 3% (as benzalkonium chloride)
Conditions and warnings: Avoid contact with the eyes
As of: 3 November 2026 · (EC) 2009/1223

EU · Annex V, entry 54Benzalkonium chloride, bromide and saccharinate (10)

Maximum concentration: 0.1% (as benzalkonium chloride)
Conditions and warnings: Avoid contact with eyes
As of: 3 November 2026 · (EC) 2009/1223