Moderate Cosmetic Ingredient NOAEL Data Sensitization Data

4-Chlororesorcinol

INCI: 4-CHLORORESORCINOL

CAS Number
95-88-5
Function
Oxidative hair dyeing (coupler — reacts with primary intermediates to form final dye)
Safety Rating
MODERATE

Regulatory Status

🇪🇺 EU Status prohibited
EU Max Conc. 2.5%
🇺🇸 US Status permitted
US Notes CIR concluded safe as used in hair dye formulations (original 1996, reaffirmed 2011). Use concentration 0.005–2%

For full compliance data across 55 jurisdictions, use the Substance Compliance tool.

Safety Data

Margin of Safety (MoS)
adequate
Dermal Absorption
low
Sensitization
moderate

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

7 study endpoints found for 4-Chlororesorcinol. 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 50 mg/kg bw/day oral rat Developmental COSMOS_DB
LOAEL 100 mg/kg bw/day oral rat Developmental COSMOS_DB
NOAEL 340 mg/kg bw/day dermal code:3484 dermal REACH
NOEL 30 mg/kg bw/day oral rat oral REACH
NOAEL 70 mg/kg bw/day oral rat oral REACH
NOAEL 70 mg/kg bw/day oral rat oral REACH
NOAEL 490.48334 mg/kg bw/day oral rat oral REACH

Sensitization Profile

Contact sensitization data for 4-Chlororesorcinol based on clinical patch test studies and IFRA standards.

Sensitization Rate
low
Allergen Class
dye
EU Allergen Listed
no
Patch Test Positive Rate
0.5%
Cross-reactivity Group
para-amino-group
Reaction Type
contact-dermatitis

Source: IVDK; NACDG; ESSCA

Expert Verdict

Moderate sensitizer — mandatory patch test warning. No evidence of carcinogenicity or reproductive/developmental toxicity at 2% dermal. Must not exceed 2.5% after mixing.

⚠️
Concern Level: High

Regulatory Flags

potential-allergen eu_cosing_listed

Frequently Asked Questions

Is 4-Chlororesorcinol safe in cosmetics?

Moderate sensitizer — mandatory patch test warning. No evidence of carcinogenicity or reproductive/developmental toxicity at 2% dermal. Must not exceed 2.5% after mixing. The EU classifies 4-Chlororesorcinol as "prohibited". Safety rating: MODERATE. 7 toxicological study endpoint(s) are available in our database.

Is 4-Chlororesorcinol allowed in the EU?

4-Chlororesorcinol EU regulatory status: prohibited. Maximum allowed concentration: 2.5%. This is based on EU Regulation 1223/2009 and its amendments.

What does 4-Chlororesorcinol do in cosmetics?

4-Chlororesorcinol functions as: Oxidative hair dyeing (coupler — reacts with primary intermediates to form final dye). It is classified as a cosmetic ingredient in our database. CAS number: 95-88-5.

What is the Margin of Safety for 4-Chlororesorcinol?

adequate The Margin of Safety (MoS) is calculated using SCCS methodology. A MoS above 100 is generally considered safe. Use the MoS Calculator tool to calculate MoS for your specific formulation and product category.

What is the NOAEL for 4-Chlororesorcinol?

The NOAEL (No Observed Adverse Effect Level) for 4-Chlororesorcinol is 50 mg/kg bw/day based on a Developmental study via oral route in rat. A total of 7 study endpoints are available. Source: COSMOS_DB.

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