Purifying Mud Mask

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

• common irritantDMDM Hydantoin, Propylene Glycol, Methylisothiazolinone

  • 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.
  • 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).
  • 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".

• exfoliating acidLactic Acid

  • Lactic Acid: An alpha hydroxy acid that loosens surface skin cells; it also makes skin more sun-sensitive while you use it. FDA, "Guidance for Industry: Labeling for Topically Applied Cosmetic Products Containing Alpha Hydroxy Acids as Ingredients" (announced at 70 FR 1721, 10 January 2005; FDA web pages title it "Labeling for Cosmetics Containing Alpha Hydroxy Acids"), which names this acid and recommends the statement "Sunburn Alert: This product contains an alpha hydroxy acid (AHA) that may increase your skin's sensitivity to the sun and particularly the possibility of sunburn."

• rich occlusiveDimethicone

  • Dimethicone: A silicone that forms a film on the surface of the skin without an oily feel. FDA OTC skin protectant monograph, 21 CFR 347.10(g), lists dimethicone as a skin protectant at 1 to 30%.

• humectantGlycerin, Panthenol

  • 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".
  • Panthenol: A provitamin B5 humectant used in products aimed at irritated and healing skin. On the humectant half: Ferreira VTP, Silva GC, Martin AA, Maia Campos PMBG, "Topical dexpanthenol effects on physiological parameters of the stratum corneum by Confocal Raman Microspectroscopy", Skin Res Technol 2023;29(9):e13317, DOI 10.1111/srt.13317, PMID 37753694, PMCID PMC10504581, open access, Introduction: "As a humectant, it has been shown to retain water more efficiently than other humectants during the last stages of dehydration..." On the soothing half, which that paper does NOT support: Cho YS, Kim HO, Woo SM, Lee DH, "Use of Dexpanthenol for Atopic Dermatitis—Benefits and Recommendations Based on Current Evidence", J Clin Med 2022;11(14):3943, DOI 10.3390/jcm11143943, PMID 35887707, open access, section 3.5: "To facilitate wound healing, dexpanthenol reduces inflammation, and promotes cell proliferation and epithelial remodeling."

• soothingZinc Oxide, Panthenol, Allantoin

  • Zinc Oxide: A mineral UV filter that the FDA also recognises as a skin protectant. FDA OTC skin protectant monograph, 21 CFR 347.10(u), lists zinc oxide as a skin-protectant active at 1 to 25%. Its labelled indication is 21 CFR 347.50(b)(3), "dries the oozing and weeping of poison: ivy, oak, sumac". The monograph does not give it the "minor skin irritation and itching" wording.
  • Panthenol: A provitamin B5 humectant used in products aimed at irritated and healing skin. On the humectant half: Ferreira VTP, Silva GC, Martin AA, Maia Campos PMBG, "Topical dexpanthenol effects on physiological parameters of the stratum corneum by Confocal Raman Microspectroscopy", Skin Res Technol 2023;29(9):e13317, DOI 10.1111/srt.13317, PMID 37753694, PMCID PMC10504581, open access, Introduction: "As a humectant, it has been shown to retain water more efficiently than other humectants during the last stages of dehydration..." On the soothing half, which that paper does NOT support: Cho YS, Kim HO, Woo SM, Lee DH, "Use of Dexpanthenol for Atopic Dermatitis—Benefits and Recommendations Based on Current Evidence", J Clin Med 2022;11(14):3943, DOI 10.3390/jcm11143943, PMID 35887707, open access, section 3.5: "To facilitate wound healing, dexpanthenol reduces inflammation, and promotes cell proliferation and epithelial remodeling."
  • Allantoin: A skin protectant used at low levels in products aimed at irritated skin. FDA OTC skin protectant monograph, 21 CFR 347.10(a), lists allantoin as a skin-protectant active at 0,5 to 2%. Its labelled indications are 21 CFR 347.50(b)(1), "temporarily protects minor: cuts, scrapes, burns", and (b)(2), which covers chafed, chapped or cracked skin. The monograph does not give it the "minor skin irritation and itching" wording; that one belongs to colloidal oatmeal, sodium bicarbonate and one combination, and to topical starch without the itching half.