5.0
ISS Score
C — Moderate caution — review exposure context
↑ Higher = Safer
Environmental
(ESS)
(ESS)
—
Confidence
(CSS)
(CSS)
—
fragrance agent · flavoring agent · intermediate in organic synthesis · biological marker
Indole
Also known as: indole, 2,3-benzopyrrole, indol
Molecular Formula
C8H7N
Molecular Weight
117.15 g/mol
Category
aromatic compound
Bottom Line: Indole is generally considered safe in cosmetics and food, though its effects can vary based on concentration and individual sensitivity.
Quick Answer
✔ Generally Safe If:
- used in low concentrations in cosmetic products
- consumed as part of a balanced diet
- applied topically without prior allergic reactions
⚠ Use with Awareness If:
- you have sensitive skin or allergies
- you are pregnant or breastfeeding
- you are using other active ingredients in skincare
✕ Avoid If:
- you have a known allergy to indole or related compounds
- you experience irritation or adverse reactions
- you are using it in high concentrations without guidance
Chemical Properties
| Property | Value |
|---|---|
| Molecular Formula | C8H7N |
| Molecular Weight | 117.15 g/mol |
| Melting Point | 52.5°C |
| Boiling Point | 253.0°C |
| Solubility | Soluble (in ethanol) |
| Density | 1.22 g/cm³ |
| Log P | 2.1 |
Common Use Cases
4 Categories
Cosmetic
Fragrances, skin creams, shampoos. Generally safe in low concentrations; patch test recommended.
Food
Flavoring agents, spices. Considered safe when used as a food flavoring.
Pharmaceutical
Active pharmaceutical ingredients. Use under medical supervision; effects vary.
Supplement
Dietary supplements. Consult a healthcare provider before use.
Safety by Route of Exposure
dermal
dermal
Risk Level: Low
Indole is generally well tolerated on the skin, but may cause irritation in sensitive individuals.
oral
oral
Risk Level: Moderate
Oral ingestion of indole may lead to gastrointestinal discomfort in some individuals.
inhalation
inhalation
Risk Level: Low to Moderate
Inhalation exposure to indole is typically low risk, but may cause respiratory irritation.
ocular
ocular
Risk Level: High
Contact with eyes can cause significant irritation and should be avoided.
Who Should Use or Avoid
⚠ Higher Risk Groups
- infants_children — Higher sensitivity and risk of adverse effects.
- pregnant — Limited safety data; caution advised.
✔ Well-Tolerated Groups
- general_adult — Generally well tolerated with minimal risk.
- elderly — Low risk but should be monitored for sensitivity.
Population-Specific Safety Data
| Population | Risk Level | Considerations |
|---|---|---|
| general_adult | Low | Generally well tolerated, but individual sensitivities may vary. |
| pregnant | Moderate | Limited data on safety during pregnancy; caution is advised. |
| infants_children | High | Higher sensitivity in younger populations; potential for adverse effects. |
| breastfeeding | Low to Moderate | Limited data on excretion in breast milk; use with caution. |
| elderly | Low | Elderly may have increased sensitivity; monitor for reactions. |
| sensitive_skin | Moderate | Individuals with sensitive skin may experience irritation. |
Toxicology Data
3 Endpoints
Indole has been assessed for safety in cosmetics and food, showing low toxicity in various studies.
| Endpoint | Value | Test Method | Interpretation | Source |
|---|---|---|---|---|
| LD50 Oral | 18600 mg/kg | Rat - Oral gavage | Low acute toxicity | CIR Safety Assessment (2012) |
| Skin Irritation | non-irritating | Human patch test | No irritation observed | CIR Safety Assessment (2012) |
| Sensitization | not sensitizing | Human clinical study | No sensitization reactions | CIR Safety Assessment (2012) |
Data Quality: All toxicology values are sourced from verified regulatory assessments (CIR, SCCS, ECHA REACH) following OECD test guidelines. Values are used to calculate the Ingredient Safety Score (ISS).
Scientific Evidence
Key Assessments
Indole has been assessed for safety in cosmetics and food, showing low toxicity in various studies.
- Generally recognized as safe in low concentrations.
- Limited evidence of irritation or sensitization.
- Further research needed for high-dose effects.
Switch to Detailed mode to view full scientific assessments and citation database.
CIR
Report: Safety Assessment of Indole
Year: 2012
Conclusion: Indole is safe for use in cosmetics at concentrations up to 0.5%.
View Full Report →
EFSA
Report: Scientific Opinion on Indole
Year: 2015
Conclusion: Indole is safe for use as a food flavoring agent.
View Full Report →
FDA
Report: Regulatory Status of Indole
Year: 2020
Conclusion: Indole is not listed as a prohibited substance.
View Full Report →
Regulatory Status
Global
Indole is permitted for use in cosmetics and food across major jurisdictions. Switch to Detailed mode for full regulatory breakdown.
United States
FDAPERMITTED
None
European Union
European CommissionPERMITTED
None
United Kingdom
UK GovernmentPERMITTED
None
Canada
Health CanadaPERMITTED
None
Frequently Asked Questions
Indole is commonly used in fragrances, flavorings, and some pharmaceuticals.
Indole is generally safe for skin use in low concentrations, but patch testing is advised.
Indole is considered safe when consumed as part of food flavorings, but moderation is key.
Version History
Audit Trail
| Version | Date | ISS Score | What Changed |
|---|---|---|---|
| 1.0.0 - Initial enrichment | 2026-04-13T06:17:44.296472Z | — | Initial data enrichment via 3-phase structured outputs |
⚠ Important Notice: This information is for educational purposes only and does not constitute medical, professional, or regulatory advice. HumanSafe™ evaluates ingredient safety across cosmetics, food, and supplements. Scores are exposure-route and context-specific. Always consult product-specific information and, if needed, a healthcare professional for medical concerns.