Is 4-n-Butylresorcinol safe in cosmetics?
4-n-Butylresorcinol has a safety rating of "GOOD" in our database. EU status: restricted. US status: permitted.
Good
Cosmetic Ingredient
4-n-Butylresorcinol
Also known as: 4-06-00-06003, BRN 1942645, 4-Butylresorcin, Butylresorcinol, UNII-2IK4UQ3ZGA (+1 more)
INCI: 4-BUTYLRESORCINOL
4-n-Butylresorcinol (CAS 18979-61-8) is a cosmetic cosmetic ingredient functioning as Tyrosinase inhibitor; TRP-1 inhibitor; melanogenesis inhibitor. EU Regulation 1223/2009 status: restricted, max ~1% leave-on face products, ~2% rinse-off. 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
Tyrosinase inhibitor; TRP-1 inhibitor; melanogenesis inhibitor
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
restricted
EU Max Conc.
~1% leave-on face products, ~2% rinse-off
US US Status
permitted
US Notes
Not restricted or prohibited by the US FDA for use in cosmetic products. No dedicated CIR safety assessment published as of 2025. EWG Skin Deep database rates low hazard. Freely used in US OTC cosmetic products without concentration restrictions. Not classified as a drug active ingredient by FDA.
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-n-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
Additional Ingredient Properties
1 property record from structured ingredient metadata.
ph_stability
{"optimal_ph_min": "5.0", "optimal_ph_max": "7.0", "stable_ph_min": "4.5", "stable_ph_max": "7.5", "degrades_above_ph": "8.0", "degrades_below_ph": "4.0", "ph_dependent_function": "Potent tyrosinase inhibitor", "formulation_note": "More stable than resorcinol", "source": "Formulation literature"}
Function Categories & List Membership
Cosmetic/Chemical Function Categories
Antioxidant
Expert Verdict
Expert safety assessment and concern-level summary for 4-n-Butylresorcinol.
Regulatory Flags
eu-annex-iii-restricted
no-sccs-opinion
limited-systemic-absorption
resorcinol-derivative
japan-quasi-drug-approved
tyrosinase-inhibitor
skin-lightening
Known Synonyms
4-06-00-06003
BRN 1942645
4-Butylresorcin
Butylresorcinol
UNII-2IK4UQ3ZGA
Rucinol (TN)
Chemical Function
Antioxidant
Frequently Asked Questions
Is 4-n-Butylresorcinol allowed in the EU?
4-n-Butylresorcinol EU regulatory status: restricted. Maximum allowed concentration: ~1% leave-on face products, ~2% rinse-off. This is based on EU Regulation 1223/2009 and its amendments.
What does 4-n-Butylresorcinol do in cosmetics?
4-n-Butylresorcinol functions as: Tyrosinase inhibitor; TRP-1 inhibitor; melanogenesis inhibitor. It is classified as a cosmetic ingredient in our database. CAS number: 18979-61-8.
Is 4-n-Butylresorcinol used outside cosmetics?
4-n-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-n-Butylresorcinol compliance across multiple jurisdictions:
Ingredient Decoder
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
Related Ingredients
Phenylethyl Resorcinol
Excellent
Same category
Tyrosinase inhibitor; TRP-1 inhibitor...
(AGARICUS BLAZEI FERMENT + GANODERMA LUCIDUM FERMENT + GANODERMA MULTIPILEUM FERMENT) EXTRACT
Good
Similar safety
Anti-sebum, Antioxidant, Skin Protecting
(ANGELICA ACUTILOBA/PAEONIA LACTIFLORA/REHMANNIA GLUTINOSA) ROOT/CNIDIUM OFFICINALE RHIZOME EXTRACT
Good
Similar safety
Skin Conditioning, Skin Conditioning ...
(ANGELICA ACUTILOBA/PAEONIA LACTIFLORA/REHMANNIA GLUTINOSA/SCUTELLARIA BAICALENSIS) ROOT/(CNIDIUM OFFICINALE/COPTIS CHINENSIS) RHIZOME/GARDENIA JASMINOIDES FRUIT/PHELLODENDRON CHINENSE BARK EXTRACT
Good
Similar safety
(ANGELICA GIGAS/GLYCYRRHIZA URALENSIS/REHMANNIA GLUTINOSA ROOT)/ANGELICA GIGAS STEM/CARTHAMUS TINCTORIUS FLOWER/(CARTHAMUS TINCTORIUS/PRUNUS PERSICA SEED)PORIA COCOS WATER
Good
Similar safety
Humectant, Skin Conditioning, Skin Pr...
(ANGELICA KEISKEI/CHRYSANTHEMUM ZAWADSKII) LEAF/STEM/CINNAMOMUM CASSIA BARK/TRICHOSANTES KIRILOWII FRUIT/ULMUS DAVIDIANA BARK/ROOT/(PAEONIA JAPONICA/BUPLEURUM FALCATUM/POLYGALA TENUIFOLIA ROOT)/VISCUS ALBUM STEM EXTRACT
Good
Similar safety
Anti-seborrheic, Anti-sebum, Antioxid...
(APPLE/CITRUS JUNOS/LENTIL/PEAR/PUMPKIN/STRAWBERRY/TOMATO FRUIT)/CORN KERNEL/(ARCTIUM LAPPA/BRASSICA OLERACEA ACEPHALA/CABBAGE/CAMELLIA SINENSIS/MORINGA OLEIFERA/RADISH/SPINACH LEAF)/(SORGHUM BICOLOR LEAF/STEM)/OAT MEAL/POTATO PULP/(CARROT/NELUMBO NUCIFERA/RADISH/WILD YAM ROOT)/(AMARANTHUS HYPOCHONDRIACUS/CASHEW/CICER ARIETINUM/COIX LACRYMA-JOBI MA-YUEN /MACADAMIA TERNIFOLIA/PHASEOLUS ANGULARIS/PISTACIA VERA/RHYNCHOSIA NULUBILIS/RICE/SESAME/SETARIA ITALICA/SOYBEAN/SWEET ALMOND/WHEAT SEED)/HORDEUM VULGARE SPROUT/CYPERUS ESCULENTUS TUBER/ARTEMISIA PRINCEPS/BROCCOLI/CHENOPODIUM QUINOA/ENTEROMORPHA COMPRESSA/HORDEUM VULGARE/IPOMOEA BATATAS/LAMINARIA JAPONICA/LENTINUS EDODES/PLEUROTUS OSTREATUS/PORPHYRA TENERA/UNDARIA PINNATIFIDA EXTRACT
Good
Similar safety
Antioxidant
4-Butylresorcinol
Good
Chemical family
Potent competitive tyrosinase inhibit...
BUTYLRESORCINOL
Good
Chemical family
Tyrosinase inhibitor / Skin lightening
4-Nitro-M-Phenylenediamine
Poor
Browse nearby
Hair dye (direct/semi-permanent)
4-Nitro-M-Phenylenediamine Sulfate
Poor
Browse nearby
Hair dye (salt form)
4-Nitro-O-Phenylenediamine
Moderate
Browse nearby
Hair colorant used in both oxidative ...
4-Nitro-O-Phenylenediamine Dihydrochloride
Moderate
Browse nearby
Hair dye (salt form)
1,4-Butanediol
Poor
Same EU status
Solvent, humectant, viscosity control...
1-Acetoxy-2-Methylnaphthalene
Good
Same EU status
Hair dyeing; colours the hair
Is 4-n-Butylresorcinol in Your Products?
Scan any product label with Piro — our free ingredient scanner. Point your camera at the ingredients list and get instant safety scores for every ingredient.
Try Piro Free →Analyze Your Full Ingredient List
Paste any INCI list into the Decoder for instant safety analysis, or calculate the Margin of Safety for 4-n-Butylresorcinol in your formulation.