Permanent Haircolor Gel, 4N Chestnut (2019 formulation)

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

• commonly dryingISOPROPYL ALCOHOL

  • ISOPROPYL ALCOHOL: A fast-evaporating solvent with a drying finish, common in toners and hand products. International Chemical Safety Card ICSC 0554, Isopropyl alcohol, prepared by an international group of experts for the ILO and WHO: "Repeated or prolonged contact with skin may cause dryness and cracking." It describes a stronger exposure than a cosmetic formula.

• common irritantPROPYLENE GLYCOL, P-PHENYLENEDIAMINE, IMIDAZOLIDINYL UREA

  • PROPYLENE GLYCOL: A solvent that shows up in patch-test clinics, more often as irritation than as allergy. American Contact Dermatitis Society, Allergen of the Year 2018 (Jacob SE, Scheman A, McGowan MA, Dermatitis 2018;29(1):3-5).
  • P-PHENYLENEDIAMINE: A hair-dye coupler and one of the most frequently positive substances in patch-test clinics. EU Regulation (EC) 1223/2009, Annex III entry 8a permits p-phenylenediamine and its salts as a hair dye substance in oxidative hair dye products, at a maximum of 2% free base applied to hair after mixing; entry 8b separately permits them in products intended for colouring eyelashes, professional use only, at the same 2% limit, so this is not a hair-dye-only restriction. The general-use wording entry 8a mandates begins with the mixing ratio, then "Hair colourants can cause severe allergic reactions", "Read and follow instructions", "This product is not intended for use on persons under the age of 16", "Temporary “black henna” tattoos may increase your risk of allergy", a three-part "Do not colour your hair if" contraindication list, "Contains phenylenediamines" and "Do not use to dye eyelashes or eyebrows". The professional-use wording PREPENDS "For professional use only." and ends "Wear suitable gloves." where the general one ends with the eyelash sentence.
  • IMIDAZOLIDINYL UREA: A preservative the FDA lists as a formaldehyde releaser, so 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 27, permits imidazolidinyl urea 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). 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.

• 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".