Restore+ Strengthen Moisturizing Shampoo (2019 formulation)

These describe what an ingredient is, not whether it is a problem. The stance marks above are the ratings; these are not.

• common irritantCOCAMIDOPROPYL BETAINE, DMDM HYDANTOIN, METHYLCHLOROISOTHIAZOLINONE, METHYLISOTHIAZOLINONE

  • COCAMIDOPROPYL BETAINE: A mild cleansing agent, but a recurring patch-test finding, usually traced to leftovers from how it is made. American Contact Dermatitis Society, Allergen of the Year 2004 (Fowler JF Jr, Dermatitis 2004;15(1):3-4).
  • DMDM HYDANTOIN: A preservative the FDA lists as a formaldehyde releaser, which is why formaldehyde-reactive skin can notice it. How much reaches the skin depends on the whole formula, not on this name alone. EU Regulation (EC) 1223/2009, Annex V entry 33, permits DMDM hydantoin as a preservative up to 0,6%. The FDA names it among the "formaldehyde and formaldehyde releasing ingredients" on its Allergens in Cosmetics page (content current 25 February 2022). SCCS Scientific Advice SCCS/1632/21, on the threshold for the "contains formaldehyde" warning, describes a study in which a moisturiser spiked to the 0,6% Annex V maximum released at least 40 ppm formaldehyde. Annex V preamble point 2, as amended by Commission Regulation (EU) 2022/1181, requires the warning "releases formaldehyde" on any product whose total released formaldehyde exceeds 0,001% (10 ppm). That Regulation states the sensitisation ground itself, so the chain is drawn by the regulator and not by us: recital (2) names the class, "Certain of those preservatives are gradually releasing formaldehyde in order to fulfil a preserving function in the final cosmetic product (so called formaldehyde releasers)", and recital (3) gives the purpose of the warning, "In order to inform consumers sensitised to formaldehyde about the presence of formaldehyde that may trigger an allergic reaction". Recital (1) records that formaldehyde is classified a skin sensitizer (Category 1) in Part 3 of Annex VI to Regulation (EC) 1272/2008.
  • METHYLCHLOROISOTHIAZOLINONE: A preservative restricted to rinse-off products in the EU because of contact-allergy reports. EU Regulation (EC) 1223/2009, Annex V entry 39 (rinse-off only, 0,0015% of a 3:1 mixture with methylisothiazolinone). The reason is in Commission Regulation (EU) No 1003/2014, recital 3, quoted rather than summarised: "The SCCS concluded that the mixture of Methylchloroisothiazolinone (and) Methylisothiazolinone in a ratio of 3:1 does not pose a risk to the health of the consumer when used as a preservative up to a maximum authorised concentration of 0,0015 % in rinse-off cosmetic products, apart from its skin sensitising potential. The SCCS indicated that induction and elicitation would be less likely in a rinse-off product than when the same concentration is present in a leave-on product." SCCS/1238/09 concludes it "is well recognised as an important skin sensitiser at current conditions of use".
  • METHYLISOTHIAZOLINONE: A preservative that patch-test clinics see reactions to often enough that the EU banned it from leave-on products. American Contact Dermatitis Society, Allergen of the Year 2013 (Castanedo-Tardana MP, Zug KA, Dermatitis 2013;24(1):2-6); SCCS Opinion on Methylisothiazolinone (P94), Submission II, SENSITISATION ONLY (SCCS/1521/13, revision of 27 March 2014); banned in leave-on cosmetics by Commission Regulation (EU) 2016/1198, which recites the need to address "the increased incidence of allergies induced by methylisothiazolinone".

• undeclared fragrance blendFRAGRANCE

  • FRAGRANCE: A blend the label does not itemize, so what is in it cannot be read from the ingredient list. EU Regulation (EC) 1223/2009 permits the collective term "parfum"; the SCCS Opinion on Fragrance Allergens (SCCS/1459/11) reviews the contact-allergy evidence for the substances it can contain.

• humectantGLYCERIN

  • GLYCERIN: A humectant, and one of the two ingredients a comparison of moisturiser components found made a significant difference to skin hydration. FDA OTC skin protectant monograph, 21 CFR 347.10(h), lists glycerin as a skin protectant at 20 to 45%. On the humectant half: Jeong CB, Han JY, Cho JC, Suh KD, Nam GW, "Analysis of electrical property changes of skin by oil-in-water emulsion components", Int J Cosmet Sci 2013;35(4):402-410, DOI 10.1111/ics.12059, PMID 23621673, found that "glycerine and urea showed significant skin hydration effects compared with other humectants".