Colorant

Basic Red 51

INCI: BASIC RED 51
CAS 77061-58-6 EC 278-601-4
2-[[4-(Dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium chloride
Limited Data
Insufficient safety data available. Consider enriching this ingredient.
Details

Description

2-[[4-(Dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium chloride

Purpose

Function

Hair dyeing (semi-permanent/direct cationic dye)
Profile

Properties

Silicone
Silicone free
Compliance

Regulatory Status

EU
Banned
Safety
POOR
US
Permitted
Absorptionlow
Sensitizationlow
MoSadequate
NOAEL10 mg/kg
ConcernModerate
Flags
eu_children_restrictedeu_cosing_listed
Verdict

Azo dye with potential reductive cleavage to dimethylaminoaniline; additional safety data was required before regulatory approval.

US Note

Not an FDA-approved color additive; coal tar hair dye exemption applies when used in hair dyes with required caution labeling

Assessment

Ratings

Comedogenic0/5
LowHigh
Irritancy0/5
LowHigh
Reference

Identifiers

CAS Number
77061-58-6
EC Number
278-601-4
INCI
BASIC RED 51
Category
Colorant
Updated
Apr 2, 2026