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BASIC RED 118.

Avoid CAS 71134-97-9 / HAIR DYEING

Basic Red 118 is a cationic azo dye primarily utilized for its ability to impart vibrant bordeaux and red-brown tones to keratinous surfaces. It is characterized by its ionic affinity for the skin and hair, offering temporary coloration without deep structural penetration.

cosmetic colorant hair dyeing

Science

This ingredient operates through electrostatic attraction, where its positively charged molecules bind to the negatively charged anionic sites found on the surface of keratin proteins. This surface-level bonding ensures the color adheres to the substrate's exterior rather than migrating into the deeper cortex or dermis.


Research

Low confidence
Effective range 0.1–1%
Optimal

0.09%

Key findings

  1. 01 Safety assessments of Basic Brown 17, which contains Basic Red 118 as a primary impurity (up to 4.5%), limit the effective safe exposure of Red 118 to approximately 0.09% in non-oxidative formulations.

Transparency

Commonly dusted
Min. effective
0.1%
Red flag below
0.05%

Due to its high pigment load and regulatory restrictions, this ingredient is frequently used at trace levels as an impurity or minor tinting agent rather than a functional skincare active.


The Formula

Solubility
Water
Optimal pH 3 – 6
0 7 14

Stability

Maintains peak stability in acidic to neutral aqueous environments; exposure to alkaline conditions (pH > 9.0) typically results in molecular degradation or significant color shifts.

Conflicts

  • anionic surfactants (e.g., Sodium Lauryl Sulfate)
  • anionic polymers (e.g., Carbomer)
  • strong oxidizing agents
  • reducing agents

Safety

CIR Status
Not reviewed
Max tested
0.09%
Pregnancy
Caution
Sensitization risk High

Currently banned as a standalone cosmetic ingredient in the EU (Annex II) due to insufficient safety data dossiers; it is only permitted when present as a controlled impurity within Basic Brown 17.


Your Skin

Yes Normal
Yes Dry
Yes Oily
No Sensitive
Irritancy High
Comedogenicity Low

Our Assessment

Avoid

While effective for temporary pigment deposition, its regulatory status and high potential for irritation make it unsuitable for precision skincare.


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