Pure Vitamin C10 Serum

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

• commonly dryingalcohol denat

  • alcohol denat: Denatured ethanol: a fast-evaporating solvent that thins a formula and leaves a dry finish. International Chemical Safety Card ICSC 0044, Ethanol (anhydrous), prepared by an international group of experts for the ILO and WHO: "The substance defats the skin, which may cause dryness or cracking." WHO Guidelines on Hand Hygiene in Health Care (2009) records depletion of the skin lipid barrier by lipid-dissolving alcohols, and also that "the lipid-dissolving effect of alcohols is inversely related to their concentration". Both describe stronger exposures than a cosmetic formula.

• common irritantpropylene glycol

  • 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).

• undeclared fragrance blendparfum/fragrance

  • parfum/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.

• exfoliating acidsalicylic acid

  • salicylic acid: A beta hydroxy acid that clears the inside of pores; the EU restricts its level and keeps it off children under three. SCCS Opinion on Salicylic Acid, Submission I (SCCS/1601/18, corrigendum of 20 to 21 June 2019); EU Regulation (EC) 1223/2009 Annex III entry 98, as amended by Commission Regulation (EU) 2021/850, which for purposes other than preservation caps it at 3,0% in rinse-off hair products, 2,0% in other products, and 0,5% in body lotion, eye shadow, mascara, eyeliner, lipstick and roll-on deodorant, and states "Not to be used in preparations for children under 3 years of age." Its separate PRESERVATIVE use sits at Annex V entry 3, capped at 0,5% (acid), where the salts carry the carve-out "except for shampoos".

• 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, sodium hyaluronate

  • 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".
  • sodium hyaluronate: A humectant that holds a large amount of water at the skin surface. Chylińska N, Maciejczyk M, "Hyaluronic Acid and Skin: Its Role in Aging and Wound-Healing Processes", Gels 2025;11(4):281, DOI 10.3390/gels11040281, PMID 40277717, open access: hyaluronic acid's "high osmotic activity and anionic structure enable it to bind large amounts of water", and "sodium and potassium hyaluronate are widely used in moisturizing products". The same review notes that high-molecular-weight hyaluronic acid does not penetrate the deeper layers.