Article 19 of the Cosmetics Regulation requires ingredients to be listed on the packaging using the common ingredient name, and this glossary is where those names are fixed. That is its entire job. It exists so that the same substance is written the same way on every label across the Union, and so that a consumer or a clinician reading an ingredient list is reading a name that means one thing.

The most common misuse follows directly from the size of it. Thirty thousand entries look like a catalogue of what may be used, and it is not one. A substance prohibited under Annex II has a common name too, because a name is needed whether or not the substance may be in a product — for enforcement documents, for safety reports, for the annexes themselves. Finding an ingredient here establishes what to call it and nothing else.

The glossary is issued as a Commission implementing decision with its own application date, which does not move when an annex is amended. So the naming of a substance and its regulatory status change on different timetables, and a current glossary entry can sit alongside a restriction added afterwards.

Used for what it is, it answers a real and frequent question: given a material with a trade name, a CAS number or a supplier's description, what has to appear in the ingredient list.