Birch Moisture Tone-Up Sunscreen

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

• humectantSodium Hyaluronate, Glycerin

  • 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.
  • 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".

• soothingZinc Oxide

  • 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.