Ingredient glossary / Preservative
Methylisothiazolinone (MI)
On the label: Methylisothiazolinone · Preservative
What it is
A preservative that caused a wave of contact allergy in the 2010s; the EU now bans it in leave-on products and limits it in rinse-off ones.
Preservatives: Preservatives stop bacteria and mould growing in a product that contains water; every water-based product needs one.
Wikidata: Chemical compound. Q423870 →
In the research
556 PubMed papers mention it with skin, cosmetics or hair; the three most recent:
- Prevalence of Contact Sensitization in Patients with Atopic Dermatitis: A Retrospective Study from China · Acta dermato-venereologica, 2026
- Mechanistic pathways of cosmetic ingredient toxicity: a critical review of in vitro and in vivo evidence · Archives of toxicology, 2026
- Stratum Corneum Biomarkers for Differentiating Irritant and Allergic Contact Dermatitis · Contact dermatitis, 2026
A paper is a paper, not a verdict: titles are listed so you can read them, and a study on cells or mice says little about a cream on a face.
Other preservatives
Dew & Balm describes ingredients from the public record and makes no claim about what a product will do for you. Statements about dietary supplements have not been evaluated by the FDA. If a product causes a reaction, stop using it; a reaction that spreads or affects breathing is a call to a doctor or 911.