What it does
The EU's CosIng database describes Decyl Glucoside as the product of condensing decyl alcohol with glucose, and lists three functions: cleansing, emulsion stabilising and cleansing surfactant.1 A cleansing surfactant, in the EU's definition, wets the surface, emulsifies or dissolves oils and holds dirt in suspension, and usually adds to a product's foam and lather.2
It belongs to the alkyl glucosides, non-ionic surfactants made by reacting glucose with fatty alcohols. A 2026 review describes the family as having a low potential for irritation and favourable ecological characteristics, being made from renewable sources and completely biodegradable.3 A review of shampoo cleansers describes non-ionic surfactants as the mildest of all, used beside ionic ones as a secondary cleanser4; shampoo surfactant types shows how the families are combined.
Where you find it
A 2026 survey of 650 products from the largest online retailer in the Netherlands found decyl glucoside in 31 of 300 rinse-off products, including 18% of baby shampoos and 10% of shampoos, and in 15 of 350 leave-on products, ten of them sunscreens: one in five of the 50 sunscreens surveyed. The same authors note that it was identified as a "hidden" allergen in a UV filter ingredient.5 In rinse-off products, its relative Coco-Glucoside was more than three times as common.5
What patch-test studies found
Alkyl glucosides are chemically stable and hardly react with proteins, so they were not predicted to cause allergy. Contact sensitisation to them is nonetheless increasingly recognised, and decyl glucoside gives 2.4% positive reactions in routine patch testing in the United States.3
In a North American series of 24,097 patients tested with decyl and/or lauryl glucoside between 2009 and 2018, 470 (2.0%) reacted. Most reactions (83.9%) were judged currently relevant; personal care products were the most common source, led by hair products (16.5%) and skin cleansers (15.2%); and among patients tested with both, more than 40% of those who reacted to one also reacted to the other.6
Not every positive test means allergy. Of 4,343 patients tested in Amsterdam between 2019 and 2026, 3.5% reacted to decyl glucoside, but doubtful reactions were common, only 1.9% of the whole group had reactions considered certainly or probably relevant, and strongly positive reactions were virtually absent, which the authors read as a sign that the test materials themselves are irritating.7 A 2026 review adds that people with a history of atopic dermatitis appear to be at higher risk, and that cleansing products for babies and children are the cosmetics most likely to contain these surfactants.8
What official sources say
Decyl Glucoside has no entry in the annexes of the EU cosmetics regulation.9 The US Cosmetic Ingredient Review assessed it with 18 other alkyl glucosides in 2013 and concluded that they are safe in the present practices of use and concentration when formulated to be non-irritating. Because enzymes in human skin are likely to break these ingredients down, the panel also drew on its earlier reports on fatty alcohols.10
How it appears on a label
As Decyl Glucoside, its name in the EU glossary.11 Its relatives end the same way: Lauryl Glucoside, Coco-Glucoside, Caprylyl/Capryl Glucoside and Cetearyl Glucoside are all alkyl glucosides. Because reactions between them often overlap, the Dutch authors advise patients already found to be sensitised to one of them to avoid products containing any alkyl glucoside.5
What sulfate-free means explains where glucosides fit among the cleansers that replace sulfates, and the shampoo ingredient checker shows the role of every name on a list.