A salt of 8-hydroxyquinoline, linked in EU data to Annex II and regulated in Annex III as a peroxide stabiliser in hair products.
What it is
Oxyquinoline sulfate is the salt of oxyquinoline (8-hydroxyquinoline) and sulfuric acid. CosIng lists it as an antimicrobial and chelating agent. The EU data link this ingredient to an entry in Annex II (prohibited substances) and to an entry in Annex III (substances subject to restrictions) covering its use as a stabiliser for hydrogen peroxide in rinse-off and leave-on hair products.
Where it is used
Found mainly in hair products that contain hydrogen peroxide, such as developers for hair colours and bleaches.
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 what the Annex II entry covers and for the applicable limits of the Annex III entry, which depend on whether the hair product is rinsed off or left on.
Functions
- Antimicrobial
- Preventing and/or slowing down microbial growth.
- Chelating
- Forming complexes with metal ions which could affect the stability and/or appearance of cosmetics.
EU regulation
- As of
- 3 November 2026 · (EU) 2019/1966
- Product type
- (a) Stabilizer for hydrogen peroxide in rinse-off hair products (b) Stabilizer for hydrogen peroxide in leave-on hair products
- Maximum concentration
- (a) (0,3 % as base) (b) (0,03 % as base)
- As of
- 3 November 2026 · (EU) 2019/1966