Is 4-Butylresorcinol safe in cosmetics?
4-Butylresorcinol has a safety rating of "GOOD" in our database. EU status: permitted. US status: permitted.
Good
Active Ingredient
4-Butylresorcinol
Also known as: 4-06-00-06003, BRN 1942645, 4-Butylresorcin, UNII-2IK4UQ3ZGA, Rucinol (TN) (+1 more)
INCI: BUTYLRESORCINOL
4-Butylresorcinol (CAS 18979-61-8) is a cosmetic active ingredient functioning as Potent competitive tyrosinase inhibitor; reversible phenolate coordination to. EU Regulation 1223/2009 status: permitted. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety data.
View industrial chemical safety profile for CAS 18979-61-8 →
Auto-generated CPSR Part A draft with source citations
Function
Potent competitive tyrosinase inhibitor; reversible phenolate coordination to the dicopper catalytic centre of tyrosinase without forming quinone intermediates; effective melanogenesis inhibition at low concentrations (0.3%); also inhibits TRP-1
Safety Rating
GOOD
Chemistry & Identifiers
IUPAC Name
4-butylbenzene-1,3-diol
InChIKey
CSHZYWUPJWVTMQ-UHFFFAOYSA-N
SMILES
CCCCC1=C(C=C(C=C1)O)O
Regulatory Status
EU EU Status
permitted
US US Status
permitted
US Notes
No FDA restriction. Used at 0.1–0.3% in OTC brightening products. Not classified as a drug. No concentration limit. Japan quasi-drug since 1998.
For full compliance data across multiple jurisdictions, use the Substance Compliance tool.
Safety Data
Margin of Safety, dermal absorption, and sensitization profile summaries for 4-Butylresorcinol.
Calculate MoS for your specific formulation with the MoS Calculator.
ECHA REACH Registration
European Chemicals Agency REACH dossier and Substances of Very High Concern listing.
Registration Type
Full
Tonnage Band
Ceased manufacture
Substance Type
SUBSTANCE
SVHC Candidate
No
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Expert Verdict
Expert safety assessment and concern-level summary for 4-Butylresorcinol.
Regulatory Flags
tyrosinase-inhibitor
brightening
dicopper-site
reversible
no-quinone
no-leukoderma
2024-ranked-strongest-among-6
concentration-dependent-cytotoxicity
dose-critical
quasi-drug-japan-1998
rucinol
melasma
hyperpigmentation
pih
eu-allowed
us-allowed
Known Synonyms
4-06-00-06003
BRN 1942645
4-Butylresorcin
UNII-2IK4UQ3ZGA
Rucinol (TN)
4-n-Butylresorcinol
Chemical Function
Antioxidant
Frequently Asked Questions
Is 4-Butylresorcinol allowed in the EU?
4-Butylresorcinol EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.
What does 4-Butylresorcinol do in cosmetics?
4-Butylresorcinol functions as: Potent competitive tyrosinase inhibitor; reversible phenolate coordination to the dicopper catalytic centre of tyrosinase without forming quinone intermediates; effective melanogenesis inhibition at low concentrations (0.3%); also inhibits TRP-1. It is classified as a Active Ingredient in our database. CAS number: 18979-61-8.
Is 4-Butylresorcinol used outside cosmetics?
4-Butylresorcinol also appears in industrial chemical safety data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.
Compliance Tools
Check 4-Butylresorcinol compliance across multiple jurisdictions:
Ingredient Decoder
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Substance Compliance
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MoS Calculator
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Heavy Metal Limits
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4-n-Butylresorcinol
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BUTYLRESORCINOL
Good
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Tyrosinase inhibitor / Skin lightening
4-Butyl-5-Methylthiazole
Good
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Fragrance / Masking agent
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