A strong inorganic alkali used as a pH adjuster and in hair straighteners, regulated in Annex III.
What it is
Lithium hydroxide is a strong inorganic base, the hydroxide of the alkali metal lithium. CosIng lists it as a buffering and hair waving or straightening ingredient. In the EU it is covered by an entry in Annex III (substances subject to restrictions).
Where it is used
Found in a small number of products, such as hair straighteners.
Limits of interpretation
The INCI list shows which ingredients are present, not how much of each. Above 1%, ingredients are listed in descending order of weight; below 1% the order is free.
See the EU regulation section for the applicable limits and conditions; according to the Annex III entry, they depend on the product type and include labelling warnings.
Functions
- Buffering
- Stabilising the pH of an aqueous medium in a narrow range even if an acid or base is added. Altering and/or maintaining a cosmetic product's pH at the desired level.
- Hair waving or straightening
- Modifying the chemical structure of the hair, allowing it to be set in the style required (permanent waves or hair straightening).
EU regulation
EU · Annex III, entry 15bLithium hydroxide
- Product type
- (a) Hair straightener (b) pH ajuster for depilatories (c) Other uses as pH ajuster (for rinse-off products only)
- Maximum concentration
- (a) 1. 2% (6) 2. 4.5% (6)
- Conditions and warnings
- (a) 1. Contains alkali Avoid contact with eyes Can cause blindness Keep out of reach of children 2. Avoid contact with eyes Can cause blindness (b) Contains alkali Keep out of reach of children Avoid contact with eyes
- As of
- 3 November 2026 · (EC) 2009/1223