Gluconolactone

Keeps the formula stable.

In the Exfoliating acids group

What it is

A compound made from glucose, a sugar. One of the exfoliating acids, of the kind known as polyhydroxy acids.

Binds metal ions that could affect the product's stability, and is used as a skin conditioning agent.

A short summary from the dictionary, not yet an in-depth article. About these entries

What it does in a formula

Keeps the formula stableOfficial EU function: Chelating

Keeps skin in good conditionOfficial EU function: Skin conditioning

Why some people watch for it

Exfoliating acids

Some people limit exfoliating acids because they can make skin more sensitive, including to the sun, or because they already use one and do not want to layer more.

A group is a fact about the ingredient, not a judgement of it.