Clinical tests with an 8% solution indicated that Polyquaternium-7 is not a photosensitiser. Given its structure, the material is considered not to be at risk of being significantly absorbed into the skin and is therefore unlikely to produce general toxicity, developmental toxicity, or mutagenic/carcinogenic effects under conditions of use. The presence of Acrylamide monomer is considered to be sufficiently low to be of no toxicological significance. Based on the available data, it is concluded that Polyquaternium-7 is safe for use in cosmetic formulations (1).

It is used as a conditioning agent in shampoos to improve the uniformity and efficiency of deposition of conditioning agents on the hair and to lubricate (2) and soften the hair to avoid frizzing (3).

Polyquaternium-7 has been used, as it is nontoxic, in an antibacterial superabsorbent hydrogel (4).

References_____________________________________________________________________

(1) Final Report on the Safety Assessment of Polyquaternium-7   International Journal of Toxicology - December 1995 vol. 14 no. 6 476-484

(2) Erazo-Majewicz P, Roberts-Howard C, Oldham E, Lynch C, Graham J, Usher CR, Joneja S. Linking enhanced deposition agent functionality with aesthetic performance. J Cosmet Sci. 2011 Mar-Apr;62(2):101-8. 

Abstract. This study examines the cationic polymers 1) guar hydroxypropyltrimonium chloride polymers (GHPTC), 2) acrylamidopropyltrimonium chloride/acrylamide copolymer (APTAC/Acm), 3) polyquaternium polymers (PQ-10, PQ-7, PQ-67), and 4) a new polymer system approach for their a) deposition efficiency (as measured by quantifying oils deposited on virgin hair) and b) ability to deliver good wet and dry lubricity to the hair from a cleansing formulation as measured by comb energy and friction characteristics of the hair samples. Conditioning polymer technology approaches 1) acrylamidopropyltrimonium chloride/acrylamide copolymer, 2) a guar hydroxypropyltrimonium chloride polymer, and 3) the new polymer system approach deliver superior deposition of natural conditioning oils and dimethicone materials from anionic/amphoteric surfactant cleansing formulations. These new polymer technologies offer formulators the ability to improve uniformity of deposition as well as deposition efficiency of conditioning agents onto hair, and target the desired hair lubricity.

(3) Gao T. Evaluation of hair humidity resistance/moisturization from hair elasticity. J Cosmet Sci. 2007 Jul-Aug;58(4):393-404.

(4)  Shen J, Li B, Zhan X, Wang L. A One Pot Method for Preparing an Antibacterial Superabsorbent Hydrogel with a Semi-IPN Structure Based on Tara Gum and Polyquaternium-7. Polymers (Basel). 2018 Jun 22;10(7):696. doi: 10.3390/polym10070696. PMID: 30960621; PMCID: PMC6403564.

Abstract. An antibacterial superabsorbent polymer was prepared by graft polymerization of acrylic acid onto tara gum polysaccharide, by adding N,N-dimethyl-N-2-propenyl-2-propen-1-aminium chloride and a polymer with 2-propenamide (polyquaternium-7, PQ7) as an antibacterial agent. The effects of the amount of PQ7 in the hydrogel on its swelling ratio were investigated and maximum swelling ratios of 712 g/g and 68 g/g, in distilled water and 0.9 wt % NaCl solution were attained with 0.5 g PQ7 per gram of tara gum. The superabsorbent hydrogel was characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermal gravimetric analysis. The results showed that poly (acrylic acid) was successfully grafted onto tara gum and a three-dimensional network structure formed with PQ7 chains penetrated in the networks. The antibacterial properties of these superabsorbent hydrogels against Staphylococcus aureus and Escherichia coli improved with increasing PQ7 content. This study demonstrates a method of preparing novel functional superabsorbent hydrogels.