Sodium Hydroxide
Fine
Official INCI name
Lye — sounds alarming, but used in tiny amounts to neutralise acids, and none of it remains free in a finished product.
What it does
pH adjuster or chelator. Keeps acidity in range and binds metal ions so the formula stays stable.
“Sodium Hydroxide” is its name in the EU glossary of common ingredient names (no. 26674), the names labels in the EU must use. © European Union, EUR-Lex.