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Annex III Entry 204 27/05/2013

DIHYDROXYINDOLINE

2,3-Dihydro-1H-indole-5,6-diol and its hydrobromide salt (see note 17).

DIHYDROXYINDOLINE is listed in Annex III and may only be used under the conditions shown in this record. Maximum concentration in this record: 2.0%.

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Restricted substance— Annex III, EU Regulation 1223/2009
Max conc.: 2.0%
Entry: 204

Chemical identity and properties

PubChem 2D chemical structure for CAS 138937-28-7
CAS 138937-28-7PubChem CID 22020437

5,6-Dihydroxyindoline hydrobromide

IUPAC name
2,3-dihydro-1H-indole-5,6-diol;hydrobromide
Molecular formula
C8H10BrNO2
Molecular weight
232.07 g/mol
Exact mass
230.98949 Da
Topological polar surface area
52.5 Ų
Hydrogen-bond donors
4
Hydrogen-bond acceptors
3
Covalent units
2
Defined stereocentres
0

Also known as

RefChem:5280725,6-Dihydroxy-2,3-dihydro-1H-indolium bromideEC 421-170-6Indoline-5,6-diol hydrobromide5,6-DIHYDROXYINDOLINE HBRDIHYDROXYINDOLINE HBRAS-173475,6-DihydroxyindolineHBr
6 more reported names
Indoline-5,6-dIndoline-5,6-diol HBrIndoline-5,6-diolhydrobromideindoline-5,6-diol;hydrobromideCS-0209156FT-0654053
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

PubChem 2D chemical structure for CAS 29539-03-5
CAS 29539-03-5PubChem CID 147311

5,6-Dihydroxyindoline

Leukoaminochrome is a member of the class of indoles that is indoline with hydroxy substituents at positions 5 and 6. It has a role as a metabolite. It is a member of indoles and a member of catechols. It derives from a hydride of an indoline. — ChEBI

IUPAC name
2,3-dihydro-1H-indole-5,6-diol
Molecular formula
C8H9NO2
Molecular weight
151.16 g/mol
Exact mass
151.063328530 Da
XLogP3
1.2
Topological polar surface area
52.5 Ų
Hydrogen-bond donors
3
Hydrogen-bond acceptors
3
Covalent units
1
Defined stereocentres
0

Also known as

Indoline-5,6-diol5,6-IndolinediolLeukoaminochromeHH49N58FJ9CHEBI:74683RefChem:10722011H-Indole-5,6-diol, 2,3-dihydro-56DHInn
9 more reported names
2-descarboxy-cyclo-dopa2,3-Dihydro-5,6-dihydroxyindole5,6-Dihydroxy-2,3-dihydroindoleLeucoaminochromeLEUCODOPAMINOCHROMEUNII-HH49N58FJ9VGSVNUGKHOVSPK-UHFFFAOYSA-NAC-27802CS-0343102
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Record details

Maximum concentration

2.0%

Product type

Hair dye substance in non-oxidative hair dye products

Warnings

- Can cause allergic reaction
- You have ever experienced any reaction afther colouring your hair
- You have experienced a reaction to a temporary 'black henna' tattoo in the past

INCI glossary name

DIHYDROXYINDOLINE

Chemical name

2,3-Dihydro-1H-indole-5,6-diol and its hydrobromide salt (see note 17).

Regulatory information

Regulation

(EC) 2013/344

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SCCS opinions

Identified ingredients

Key data

CAS
29539-03-5 - 138937-28-7
EC
- - 421-170-6
Annex
III
Entry number
204

Inventory links for DIHYDROXYINDOLINE

Annex III 190
Shared product type

ACID BLUE 9

CAS: 3844-45-9 - 2650-18-2 - 68921-42-6
EC: 223-339-8 - 220-168-0 - 272-939-6
Annex III 191
Shared product type

CURRY RED

CAS: 25956-17-6
EC: 247-368-0
Annex III 192
Shared product type

ACID RED 18

CAS: 2611-82-7 - 12227-64-4
EC: 220-036-2 - 235-438-3
Annex III 193
Shared product type

ACID RED 52

CAS: 3520-42-1
EC: 222-529-8
Annex III 195
Shared product type

ACID BLUE 62

CAS: 4368-56-3
EC: 224-460-9

What Annex III means for DIHYDROXYINDOLINE

DIHYDROXYINDOLINE 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 2 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: 2.0%
  • Confirm product type compatibility: Hair dye substance in non-oxidative hair dye products
  • Include required warning statement on product label.
  • Document conditions of use in the Product Information File (PIF).

Frequently asked questions

DIHYDROXYINDOLINE is listed in Annex III of EU Regulation 1223/2009 as a restricted substance. It may only be used under the conditions specified in the entry, including any maximum concentration, product type limitation and required warning statements shown above.

CAS 29539-03-5 - 138937-28-7 is the unique numerical identifier assigned to DIHYDROXYINDOLINE by the Chemical Abstracts Service. In cosmetic compliance work, the CAS number is used to cross-reference the substance across regulatory databases, raw material specifications and safety assessment reports. Multiple EU annex entries may share the same CAS number if the same substance appears under different conditions or in different annexes.

The maximum concentration of 2.0% applies to the concentration of the substance in the ready-to-use cosmetic product. When the substance is supplied as part of a blend or mixture, the calculation must account for the contribution of all sources in the formulation. The combined concentration must not exceed the stated limit.

Use the INCI Checker tool on this site to paste your full ingredient list (INCI) and scan it against all Annex II–VI entries. The tool highlights any ingredients that match restricted, prohibited or allergen-flagged records. This is useful for rapid compliance screening of finished product formulas or raw material declarations.
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Source note for Annex III record DIHYDROXYINDOLINE

This page summarizes one Annex III record for DIHYDROXYINDOLINE 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 DIHYDROXYINDOLINE, but confirm any final regulatory decision against the current official annex wording and source files.

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