Polyquaternium-7 on your skin: a safety profile

What is polyquaternium-7?

The IUPAC name is poly(dimethyliminium chloride 1,3-propanediyl).

Also known as: poly(dimethyliminium chloride 1,3-propanediyl), polycationic polymer, NICKEL FLUORIDE, difluoronickel.

IUPAC name

poly(dimethyliminium chloride 1,3-propanediyl)

CAS number

26590-05-6

Molecular formula

(C12H28ClNO2)n

Regulatory consensus

1 regulatory bodyhas classified Polyquaternium-7.

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where you encounter polyquaternium-7

• conditioner
• hair treatment
• styling products
• skin care

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Polyquaternium-7:

• Decyl glucoside or other alkyl polyglucosides (APGs) — milder, plant-derived
  Trade-offs: Consumer preference for 'natural' label; many natural fragrance compounds are potent allergens (limonene, linalool, eugenol); 'natural' ≠ 'safe'; often more expensive than synthetic equivalents.
  Relative cost: 2-5× conventional
• Sodium cocoyl isethionate (SCI) — low irritation potential
  Trade-offs: Alternative surfactant; performance characteristics (foaming, emulsification, wetting) vary; biodegradability and aquatic toxicity should be assessed; formulation adjustment may be needed.
  Relative cost: 1.2-2×
• Sodium lauroyl glutamate — amino acid-based, very mild
  Trade-offs: Extremely mild (pH 5.5-6.5); biodegradable; derived from amino acids and fatty acids; premium ingredient cost; excellent consumer perception; lower foam volume than sulfate surfactants.
  Relative cost: 1.2-2×
• Cocamidopropyl betaine (amphoteric) — gentler than anionic surfactants
  Trade-offs: Removes 95-99% of dissolved contaminants including metals, PFAS, nitrates; wastes 2-4 gallons per gallon produced (improving with newer systems); removes beneficial minerals; $0.05-0.25/gallon; requires pre-treatment for longevity.
  Relative cost: 1.2-2×

Frequently asked questions