ACID RED 18
Trisodium 1-(1-naphthylazo)-2-hydroxynaphthalene-4',6,8-trisulphonate and aluminium lake (Cl 16255) (see note 17).
ACID RED 18 is listed in Annex III and may only be used under the conditions shown in this record. Maximum concentration in this record: 0.5%.
Chemical identity and properties
Ponceau 4R aluminum
- IUPAC name
- aluminum 7-hydroxy-8-[(4-sulfonatonaphthalen-1-yl)diazenyl]naphthalene-1,3-disulfonate
- Molecular formula
- C20H11AlN2O10S3
- Molecular weight
- 562.5 g/mol
- Exact mass
- 561.9391215 Da
- Topological polar surface area
- 242.0 Ų
- Hydrogen-bond donors
- 1
- Hydrogen-bond acceptors
- 12
- Covalent units
- 2
- Defined stereocentres
- 0
Also known as
5 more reported names
Evidence from additional scientific databases
NIH PubChem PUG-View
Attributed physical-property, hazard, environmental and use annotations.
- Note: This chemical does not meet GHS hazard criteria for 100% (5 of 5) of all reports. Source: European Chemicals Agency (ECHA)
- GHS Hazard Statements: Not Classified; Reported as not meeting GHS hazard criteria by 5 of 5 companies. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
- ECHA C&L Notifications Summary: Aggregated GHS information provided per 5 reports by companies from 1 notifications to the ECHA C&L Inventory.; Reported as not meeting GHS hazard criteria per 5 of 5 reports by companies.; There are 0 notifications provided by 0 of 5 reports by companies with hazard statement code(s).; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record
Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.
Additional source coverage and match status
| Source | Result | Checked |
|---|---|---|
| NIH PubChem PUG-View | Exact match | 2026-08-31 |
A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.
Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.
C.I. Acid Red 18, trisodium salt
- IUPAC name
- trisodium;7-hydroxy-8-[(4-sulfonatonaphthalen-1-yl)diazenyl]naphthalene-1,3-disulfonate
- Molecular formula
- C20H11N2Na3O10S3
- Molecular weight
- 604.5 g/mol
- Exact mass
- 603.92689092 Da
- Topological polar surface area
- 242.0 Ų
- Hydrogen-bond donors
- 1
- Hydrogen-bond acceptors
- 12
- Covalent units
- 4
- Defined stereocentres
- 0
Also known as
16 more reported names
External database identifiers
- EPA DTXSID:DTXSID9021213
Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.
Record details
Maximum concentration
0.5%
INCI glossary name
ACID RED 18
Chemical name
Trisodium 1-(1-naphthylazo)-2-hydroxynaphthalene-4',6,8-trisulphonate and aluminium lake (Cl 16255) (see note 17).
Chemical / IUPAC name
Trisodium 1-(1-naphthylazo)-2-hydroxynaphthalene-4',6,8-trisulphonate and aluminium lake (Cl 16255)
Regulatory information
SCCS opinions
Identified ingredients
Key data
Inventory links for ACID RED 18
Related records for ACID RED 18
CI 19140 / ACID YELLOW 23
ACID BLUE 9
6-METHOXY-2-METHYLAMINO-3-AMINOPYRIDINE HCL
What Annex III means for ACID RED 18
ACID RED 18 is a restricted substance under Annex III of EU Cosmetics Regulation 1223/2009. Its use in cosmetics is only permitted under the specific conditions set out in the entry above, including applicable concentration limits, product type restrictions and required warning statements.
When including this substance in a formulation, all conditions — maximum concentration, product scope and warning labels — must be met simultaneously. Compliance with one condition does not override the others.
This record is linked to 3 CosIng inventory ingredients for name and identifier cross-reference. The page also surfaces 12 related annex records with overlapping identifiers, annex logic or naming patterns.
Compliance checklist
- Ensure formulation concentration does not exceed: 0.5%
- Confirm product type compatibility: Hair dye substance in non-oxidative hair dye products
- Document conditions of use in the Product Information File (PIF).
Frequently asked questions
Source note for Annex III record ACID RED 18
This page summarizes one Annex III record for ACID RED 18 from public European Commission cosmetic materials and adds linked inventory or identifier matches when available.
Use this record page to review Annex III conditions for ACID RED 18, but confirm any final regulatory decision against the current official annex wording and source files.
Tools & next steps
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