Fragrance avoidance
No fragrance-linked caution surfaced in the current profile.
This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.
- beauty
- industrial
5,6-Dihydroxyindoline
CAS 29539-03-5 · 70/100 · High conf.
Concern score
70/100High concern based on regulatory listings.
High confidence
5,6-Dihydroxyindoline in plain language
On cosmetic ingredient lists it appears as “Dihydroxyindoline”.
Also known as Dihydroxyindoline · DIHYDROXYINDOLINE HBr · 2,3-Dihydro-1H-indole-5,6-diol · 5,6-INDOLINEDIOL · 1H -Indole-5,6-diol, 2,3-dihydro- · 2,3-Dihydro-1H -indole-5,6-diol
Show all 17 names
2,3-Dihydro-1H-Indole-5,6-Diol; 5,6-Indolinediol · 2,3-Dihydro-5,6-dihydroxyindole · 2-descarboxy-cyclo-dopa · 5,6-Dihydroxy-2,3-dihydroindole · 56DHInn · Indoline-5,6-diol · Leucoaminochrome · Leucodopaminochrome · Leukoaminochrome · UNII-HH49N58FJ9 · Vgsvnugkhovspk-uhfffaoysa-n
Used in cosmetics as a hair dye.
- Hair dyeing
- Colourant
- High concern: no hazard classifications on record. It is restricted in EU cosmetics.
Why it's flagged
2,3-Dihydro-1H-indole-5,6-diol and its hydrobromide salt (see note 17). is restricted in cosmetic products under Annex III of the EU Cosmetics Regulation (EC) 1223/2009.
RestrictedEU EC — restricted
The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.
Regulation
Restrictions first, then routine listings from published regulatory sources.
- EU Annex III — restricted
- EU restricted in cosmetics
- Found in consumer products
- Industrial
- View source →restricted
EUEC
Annex III of EU Cosmetics Regulation (EC) 1223/2009: substances which cosmetic products must not contain except subject to the restrictions laid down. Product types: Hair dye substance in non-oxidative hair dye products Maximum concentration: 2.0% Conditions of use and 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
USEPAcommercial use observedEPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.
- EPA CPDat observed this chemical in 0 composition records across product categories including unclassified products. EPA CPDat classifies this chemical for functional uses including Dye.Source →
USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
- openFDA substance registry classifies this ingredient as chemical.Source →
Expert safety opinions
No expert opinion on file for 5,6-Dihydroxyindoline. These are the independent scientific bodies that assess ingredients like this one; we show an opinion only when a record we hold cites it.
SCCS
EU Scientific Committee on Consumer Safety
No SCCS opinion on file.
CIR
Cosmetic Ingredient Review (US expert panel)
No CIR safety assessment on file.
Evidence & sources
No graded research studies for 5,6-Dihydroxyindoline yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.
Where this comes from
- Open →
CosIng
regulatory · updated 2026-09-23
- Open →
EU CosIng Cosmetics Regulation Annexes
regulatory · updated 2013-05-27
- Open →
EPA Chemical and Products Database
exposure · updated 2019-12-20
- Open →
EPA DSSTox Identifiers
chemistry · updated 2025-12-29
- Open →
FDA GSRS UNII
registry · updated 2026-02-26
- Open →
openFDA Substance
registry · updated 2026-05-24
- Open →
PubChem Live Enrichment
chemistry · updated 2026-05-17
Suitability
Context-specific fit derived from published classifications and the current ingredient evidence profile.
Good fit
Found in these products
Cosmetic and personal-care products that list 5,6-Dihydroxyindoline are shown first. Their ingredient lists include 5,6-Dihydroxyindoline; each product's own rating depends on its whole formula, so it is shown on the product page, not here.
