In the INCI lists of professional shampoos, conditioners, masks and styling products, a number preceded by the prefix “Polyquaternium” appears almost systematically. Polyquaternium-7, Polyquaternium-10, Polyquaternium-32, Polyquaternium-55 — behind these names lies a family of cationic polymers with distinct molecular architectures. Understanding their differences enables intelligent reading of an INCI list and explains why one product conditions differently from another. Hairswiss decodes.

What is a Polyquaternium? Chemical definition

A Polyquaternium is a water-soluble cationic polymer carrying quaternary ammonium groups (N⁺) distributed along its chain or as pendant groups. The density of positive charges — expressed as cationic charge density (meq/g) — directly determines the polymer’s affinity for the hair fiber surface, which is naturally negatively charged at physiological pH (4.5–5.5).

The numbers following the prefix “Polyquaternium” are not performance indices or concentration indicators — they are simple INCI registration numbers assigned chronologically by the CTFA (Cosmetic, Toiletry, and Fragrance Association). Each number corresponds to a distinct polymer structure with its own molecular weight, charge density and functional properties.

Adsorption mechanism on the hair fiber

The hair fiber presents a globally anionic surface at neutral-acid pH: the carboxylate (–COO⁻) and sulfate (–OSO₃⁻) groups of keratin, along with negatively charged amino acid residues (aspartic acid, glutamic acid), expose accessible anionic sites on the cuticle surface. Polyquaterniums, positively charged, adsorb there through electrostatic interaction: a non-covalent but extremely stable bond under cosmetic use conditions.

This adsorption is substantive: the polymer remains fixed on the fiber after rinsing, resistant to displacement by pure water. Substantivity is proportional to molecular weight and charge density — a high-molecular-weight, high-cationic-density Polyquaternium deposits a more durable film than a lighter polymer.

The main structures of the Polyquaternium family

Polyquaternium-7 (acrylamide/MAPTAC copolymer)

Structure: copolymer of acrylamide and methacrylamidopropyltrimethylammonium chloride (MAPTAC). High molecular weight (>1 MDa). Low charge density (5–15% cationic monomers). Result: flexible, non-stiffening film, excellent surface lubrication. Standard conditioning ingredient in professional shampoos — it softens without weighing down. Present in many formulations for its excellent cost-performance ratio.

Polyquaternium-10 (quaternary cellulose)

Structure: hydroxyethylcellulose modified with trimethylammonium groups. Its cellulosic base gives it relative biodegradability and compatibility with anionic surfactants. Widely used in 2-in-1 shampoos as it deposits a conditioning film on application while being partially washed off during rinsing, avoiding accumulation.

Polyquaternium-32 (acrylamide/DADMAC copolymer)

Structure: copolymer of acrylamide and diallyldimethylammonium chloride (DADMAC). High molecular weight. Its specificity lies in its marked film-forming and antistatic effect: the cationic charge density effectively neutralizes the negative charges accumulated on the fiber (responsible for static frizz), while depositing a uniform protective film. Less widespread than PQ-7 in mass-market formulations, it is preferred in dermatological cleansers and face-body care products for its cuticular mildness. In professional hair cosmetics, it appears in conditioners and conditioning creams with a strong smoothing effect.

Polyquaternium-37 (quaternary acrylate microgel)

Structure: cross-linked acrylate polymer in microgel form. Its particularity: it behaves simultaneously as a conditioning and structuring agent. At light film density on the fiber, it improves manageability; at higher concentration in styling fluids, it provides flexible hold without residue. Used in professional styling fluids and leave-in treatments.

Polyquaternium-55 (VP/dimethylaminoethylmethacrylate copolymer)

Structure: copolymer of vinylpyrrolidone and quaternized dimethylaminoethylmethacrylate. Combines the film-forming properties of PVP with cationic substantivity. Provides shape memory to curls and waves, thermal protection from the polymer film, and lasting frizz reduction. A more recent generation, preferred in reconstructive masks and high-performance hair treatments.

Measurable effects of Polyquaterniums on the hair fiber

• Antistatic action: neutralization of negative surface charges eliminates the electrostatic attraction between fibers that causes anarchic swelling and frizz. Measurable by triboelectrometry — reduction of 40–70% of surface charges depending on concentration and MW.
• Cuticle smoothing: the deposited cationic film fills cuticular surface irregularities and reduces the inter-fiber friction coefficient, improving glide and shine.
• Mechanical and thermal protection: high-molecular-weight polymers (PQ-37, PQ-55) form a thicker film that partially absorbs heat and mechanical friction stress.
• Reduction of differential porosity: by filling the cuticular gaps of porous hair, they equalize water absorption and reduce dimensional variations of the fiber in humid conditions.

How to read Polyquaterniums in an INCI list

Position in the INCI list approximately indicates concentration: ingredients are listed in descending order above 1%. Finding a Polyquaternium in the second half of the list generally means a concentration of 0.1–1% — sufficient for fiber adsorption but insufficient for a marked film-forming effect. In the first half (notably after Aqua and the main surfactants), concentration is significant and the conditioning effect will be perceptible from the first application.

The presence of several different Polyquaterniums in a single formulation is a deliberate formulation strategy: a low-MW PQ ensures rapid deposition and immediate cuticle adsorption; a high-MW PQ ensures substantivity and durability. Formulators combine them to cover both immediate sensory effect and long-term performance.

Polyquaterniums in professional products on cliCHair

The cliCHair.ch range integrates Polyquaterniums as identifiable functional actives in their published INCI lists. Two examples illustrate the generational differences between polymers.

Regeneration Therapy Mask — Edelstein

The INCI list of this reconstructive mask includes Polyquaternium-55 alongside Cetrimonium Chloride, hydrolyzed keratin and tartaric acid. The PQ-55 — VP/DMAEMA copolymer — provides its dual function here: cationic adsorption on the damaged cuticle and shape memory for curls. Its presence in a reconstructive mask (long application, often under heat) optimizes its adsorption and substantivity. The Regeneration Therapy Mask is available on cliCHair.ch.

Intensive Remedy Shampoo — Edelstein

This professional shampoo integrates Polyquaternium-7 — high-molecular-weight acrylamide/MAPTAC copolymer — between the main surfactants (Sodium Laureth Sulfate, Cocamidopropyl Betaine) and the botanical actives (Vitis Vinifera extract, Olea Europaea oil). Its position in the list indicates a significant concentration, justifying the conditioning effect advertised from the first wash. The Intensive Remedy Shampoo is available on cliCHair.ch.

What Hairswiss concludes

Polyquaterniums are not a homogeneous category: each number designates a distinct polymer architecture with its own adsorption, substantivity and fiber-effect properties. PQ-7 for light conditioning in shampoos; PQ-10 for 2-in-1 formulations; PQ-32 for antistatic action and smoothing; PQ-37 for flexible styling; PQ-55 for shape memory and thermal protection. Reading an INCI list intelligently starts with knowing which Polyquaternium you’re looking at — and what it can actually do on the fiber.