Is Dihydroxyindoline safe in cosmetics?
Dihydroxyindoline has a safety rating of "GOOD" in our database. EU status: restricted. US status: permitted. 10 toxicological study endpoint(s) are available in our database.
Dihydroxyindoline
Also known as: 1H -Indole-5,6-diol, 2,3-dihydro-, 2,3-Dihydro-1H -indole-5,6-diol, 5,6-Indolinediol, Leucodopaminochrome
INCI: DIHYDROXYINDOLINE
Dihydroxyindoline (CAS 29539-03-5) is a cosmetic cosmetic ingredient functioning as Hair dyeing — non-oxidative direct dye (melanin precursor). Reported NOAEL =10 mg/kg/day in rat (SCCNFP Opinion); EU Regulation 1223/2009 status: restricted. Industrial safety data is also available in the chemical safety database.
View industrial chemical safety profile for CAS 29539-03-5 →
Function
Hair dyeing — non-oxidative direct dye (melanin precursor)
Editorial assessment
GOOD
Preliminary editorial note — not a computed safety verdict.
Chemistry & Identifiers
IUPAC Name
2,3-dihydro-1H-indole-5,6-diol
InChIKey
VGSVNUGKHOVSPK-UHFFFAOYSA-N
Regulatory Status
EU EU Status
restricted
US US Status
permitted
US Notes
Permitted under coal-tar hair dye exemption (FD&C Act §601(a)); must carry statutory caution labeling
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for Dihydroxyindoline.
Calculate MoS for your specific formulation with the MoS Calculator.
Toxicological Studies
10 study endpoints found for Dihydroxyindoline. NOAEL (No Observed Adverse Effect Level) values are used to calculate the Margin of Safety per SCCS methodology.
| Endpoint | Value | Route | Species | Study Type | Source |
|---|---|---|---|---|---|
| NOAEL | =10 mg/kg/day | dermal | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =10 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg/day | dermal | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =10 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg/day | dermal | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg | oral | rat | dermal absorption | SCCNFP Opinion |
| NOAEL | =10 mg/kg bw/day | oral | rat | repeated dose toxicity | SCCNFP Opinion |
| NOAEL | =10 mg/kg/day | dermal | rat | repeated dose toxicity | SCCNFP Opinion |
Expanded Jurisdictional Detail
Additional regulatory detail beyond the 7-jurisdiction summary: Saudi SFDA, Korea MFDS, ASEAN ACD, Japan/Korea, Brazil/India, and cross-jurisdictional restriction entries.
Additional Jurisdictional Restrictions (1)
| Jurisdiction | Status | Max % | Product Type |
|---|---|---|---|
| BR | permitted_hair_dye | - | Non-oxidative hair dye |
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Dye
Editorial summary
Preliminary editorial summary for Dihydroxyindoline — not a computed safety verdict. See the sourced toxicological data above.
NOAEL Studies Summary
View details ->Public NOAEL study rows linked to Dihydroxyindoline by CAS number or substance name.
Studies
24
Lowest NOAEL
10
Highest NOAEL
240
Units vary across source rows: mg/kg/day, mg/kg, mg/kg bw/day
SCCNFP Opinion
Known Synonyms
1H -Indole-5,6-diol, 2,3-dihydro-
2,3-Dihydro-1H -indole-5,6-diol
5,6-Indolinediol
Leucodopaminochrome
Chemical Function
Dye
Frequently Asked Questions
Is Dihydroxyindoline allowed in the EU?
Dihydroxyindoline EU regulatory status: restricted. This is based on EU Regulation 1223/2009 and its amendments.
What does Dihydroxyindoline do in cosmetics?
Dihydroxyindoline functions as: Hair dyeing — non-oxidative direct dye (melanin precursor). It is classified as a cosmetic ingredient in our database. CAS number: 29539-03-5.
What is the NOAEL for Dihydroxyindoline?
The NOAEL (No Observed Adverse Effect Level) for Dihydroxyindoline is =10 mg/kg/day based on a repeated dose toxicity study via dermal route in rat. A total of 10 study endpoints are available. Source: SCCNFP Opinion.
Compliance Tools
Check Dihydroxyindoline compliance across multiple jurisdictions:
Ingredient Decoder
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82 Allergen Checker
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Substance Compliance
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MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
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