Bye Bye Dark Spots Niacinamide Serum

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

• 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).

• fragrance materialLimonene, Geraniol, Citronellol

  • Limonene: A citrus-smelling fragrance component named separately on the label; the one name covers three related isomers. EU Regulation (EC) 1223/2009, Annex III entry 88: a fragrance substance whose presence must be indicated in the list of ingredients above 0,001% in leave-on and 0,01% in rinse-off products, because of established contact-allergy risk. That entry carries transition footnote (37): stock that does not comply, lawfully placed on the Union market before the 31 July 2026 cut-off, may still be made available until 31 July 2028. It is marked on the racemic dl-limonene/Dipentene line and the (S)-(l-limonene) line, but NOT the (R)-p-mentha-1,8-diene (d-limonene) line, CAS 5989-27-5, whose duty was already running as entry 88 before Commission Regulation (EU) 2023/1545 and so needed no transition. All three isomers are declared under the single glossary name "Limonene", so that name on a label does not identify which of them is present.
  • Geraniol: A rose-scented fragrance component named separately on the label. EU Regulation (EC) 1223/2009, Annex III entry 78: a fragrance substance whose presence must be indicated in the list of ingredients above 0,001% in leave-on and 0,01% in rinse-off products, because of established contact-allergy risk.
  • Citronellol: A rose-and-citrus fragrance component named separately on the label. EU Regulation (EC) 1223/2009, Annex III entry 86: a fragrance substance whose presence must be indicated in the list of ingredients above 0,001% in leave-on and 0,01% in rinse-off products, because of established contact-allergy risk.

• 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".

• 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".

• soothingNiacinamide

  • Niacinamide: A vitamin B3 form that supports the skin barrier and has anti-inflammatory activity; it turns up in products aimed at acne, rosacea and eczema. Camillo L, Zavattaro E, Savoia P, "Nicotinamide: A Multifaceted Molecule in Skin Health and Beyond", Medicina (Kaunas) 2025;61(2):254, DOI 10.3390/medicina61020254, PMID 40005371, open access: it "is extensively used in ... the treatment of dermatological conditions such as blistering diseases, atopic dermatitis, rosacea, and acne vulgaris", and contributes to reducing inflammation. On the acne evidence specifically: Liu H, Yu H, Xia J, Liu L, Liu GJ, Sang H, Peinemann F, "Topical azelaic acid, salicylic acid, nicotinamide, sulphur, zinc and fruit acid (alpha-hydroxy acid) for acne", Cochrane Database Syst Rev 2020;5:CD011368, DOI 10.1002/14651858.CD011368.pub2, PMID 32356369, records "low-quality evidence" for every nicotinamide comparison it could pool, and none of its four nicotinamide studies measured the physician global assessment at all.