Get a Free 5ml Mini Now Free 5ml Mini With Every Order of The Mantle
Moumoujus

INDOLE.

Avoid CAS 120-72-9 / PERFUMING

Indole is primarily utilized as a fragrance compound, characterized by a potent, fecal aroma at high concentrations that transforms into a delicate floral note when present in trace amounts. It serves as a perfumery fixative and a fragrance component in a variety of cosmetic products, lacking any identified direct skincare benefits.

Summary

Perfuming

Research

Clinical Evidence

Low confidence
Effective range N/A
Optimal

N/A

Transparency

Dusting Analysis

Not commonly dusted

The Formula

Formulation

Solubility
Both
Optimal pH N/A
0 7 14

Stability

Indole exhibits a pH of approximately 5.9 in a 1000 g/l aqueous solution at 20 °C. Its sensory profile is highly concentration-dependent, contributing a delicate floral note at trace levels while imparting a harsh, fecal odor at higher concentrations. A critical formulation concern is its propensity to undergo nitrosation, forming potentially carcinogenic N-nitrosamines, if nitrosating agents are present. Additionally, indole can react with aldehydes to produce Schiff bases, which may lead to unwanted coloration in cosmetic and perfumery products.

Conflicts

  • Nitrosating agents
  • Aldehydes

Safety

Safety Profile

CIR Status
Not reviewed
Max tested
0.1%
Sensitization risk Moderate

The Cosmetic Ingredient Review (CIR) Expert Panel has not conducted a safety assessment for Indole (CAS 120-72-9) itself as a standalone skincare ingredient, though related indole derivatives have been reviewed for specific applications. The FDA does not require pre-market approval for most cosmetic ingredients. Globally, Indole is classified by GHS as 'Harmful if swallowed', 'Toxic in contact with skin', 'Causes serious eye irritation', and 'Skin sensitising'. While GHS indicates skin sensitisation risk, a safety assessment by the Research Institute for Fragrance Materials (RIFM) concluded that indole does not pose a skin sensitization concern at its typical, trace-level usage (generally below 0.1%) as a fragrance ingredient.

Your Skin

Skin Compatibility

No Normal
No Dry
No Oily
No Sensitive
Irritancy Unknown
Comedogenicity Unknown

Our Assessment

Verdict

Avoid

Indole is primarily used as a trace fragrance component; however, its GHS classifications as a sensitizer and skin toxicant, coupled with potential for carcinogenic N-nitrosamine formation and aldehyde reactions, make it unsuitable for precision skincare formulations.

Related

Similar Ingredients

Finding similar ingredients…