Good Cosmetic Ingredient NOAEL Data

L-Tryptophan

Also known as: (S)-2-Amino-3-(1H-indol-3-yl)propanoic acid, Triptophan, L-TRYPTOPHAN (AMINO ACID), Alanine, 3-indol-3-yl-, L-alpha-Aminoindole-3-propionic acid (+15 more)

INCI: TRYPTOPHAN

L-Tryptophan (CAS 73-22-3) is a cosmetic cosmetic ingredient functioning as Antistatic, Hair conditioning, Masking. NOAEL 1200 mg/kg bw/day (cross-referenced against ToxValDB ECHA IUCLID); EU Regulation 1223/2009 status: permitted. Industrial safety data is also available in the chemical safety database. Same-CAS public records also appear in industrial chemical safety and pharmaceutical data.

View industrial chemical safety profile for CAS 73-22-3 →

Auto-generated CPSR Part A draft with source citations
CAS Number
73-22-3
View industrial chemical safety profile →
Function
Antistatic, Hair conditioning, Masking
Safety Rating
GOOD

Chemistry & Identifiers

Formula
C11H12N2O2
MW
204.22 g/mol
EC Number
200-795-6
PubChem CID
6305
IUPAC Name
(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid
InChIKey
QIVBCDIJIAJPQS-VIFPVBQESA-N
ChEBI: CHEBI:16828 UNII: 8DUH1N11BX Wikidata: Q181003

Regulatory Status

EU EU Status permitted
US US Status permitted
US Notes Listed on US TSCA inventory and FDA food substance database; no cosmetic-specific restrictions for topical use

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

Safety Data

Margin of Safety, dermal absorption, and sensitization profile summaries for L-Tryptophan.

Calculate MoS for your specific formulation with the MoS Calculator.

Toxicological Studies

9 study endpoints found for L-Tryptophan. 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 400 mg/kg bw/day oral swine Short Term Toxicity COSMOS_DB
NOAEL 500 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 1000 mg/kg bw/day oral rat Special Toxicology Study COSMOS_DB
NOAEL 1153 mg/kg bw/day oral rat Subchronic COSMOS_DB
NOAEL 1250 mg/kg bw/day oral rat Carcinogenicity COSMOS_DB
NOAEL 1600 mg/kg bw/day oral swine Short Term Toxicity COSMOS_DB
NOAEL 3750 mg/kg bw/day oral mouse Carcinogenicity COSMOS_DB
NOAEL 5000 mg/kg bw/day oral rat Short Term Toxicity COSMOS_DB
NOAEL 7500 mg/kg bw/day oral mouse Short Term Toxicity COSMOS_DB

Pre-Calculated Safety Assessment

Pre-calculated NOAEL → SED → MoS audit trail for L-Tryptophan across SCCS product categories, with measured dermal absorption where available.

EPA ToxValDB — Toxicity Values

10 toxicity values from EPA ToxValDB (aggregated from CCTE, HPV, ToxRefDB, IRIS, and other regulatory dossiers).

Endpoint Value Species Route Duration Source
NOEL =2000 mg/kg-day Mouse oral short-term ECOTOX
NOEL =2000 mg/kg-day Rat oral acute ECOTOX
NOEL =2000 mg/kg-day Rat oral short-term ECOTOX
NOEL =2000 mg/kg-day Rat oral short-term ECOTOX
LEL >2500 mg/kg-day Rat oral chronic ToxRefDB
LEL =1250 mg/kg-day Rat oral chronic ToxRefDB
LEL =3750 mg/kg-day Mouse oral chronic ToxRefDB
LEL =3750 mg/kg-day Mouse oral chronic ToxRefDB
LOAEL >2500 mg/kg-day Rat oral chronic ToxRefDB
LOAEL >2500 mg/kg-day Rat oral chronic ToxRefDB

ECHA REACH Registration

European Chemicals Agency REACH dossier and Substances of Very High Concern listing.

Registration Type
Full
Tonnage Band
100 - 1,000 tonnes
Substance Type
SUBSTANCE
SVHC Candidate
No

Additional Ingredient Properties

3 property records from structured ingredient metadata.

acne
{"cas_number": "73-22-3", "anti_acne_mechanism": "anti_inflammatory", "comedogenicity_rating_0_to_5": "0", "acne_type_efficacy": "inflammatory", "sebum_reduction_pct_clinical": "0-5", "prescription_required_usa": "No", "otc_drug_monograph_category": "No", "max_otc_concentration_pct": "No limit", "japan_quasi_drug_anti_acne": "No", "korea_functional_cosmetic_acne": "No", "eu_cosmetic_restriction_ac…
anti_aging
{"anti_aging_claim": "barrier-repair", "mechanism_of_action": "Building block for proteins, NMF component", "target_skin_layer": "epidermis", "collagen_stimulation": "Mild", "elastin_protection": "Mild", "wrinkle_reduction_pct": "4-8", "clinical_study_duration_weeks": "8", "sample_size": "25", "double_blind": "No", "placebo_controlled": "Yes", "published_journal": "Int J Cosmet Sci", "improvement_…
self_tanning
{"cas_number": "73-22-3", "ingredient_class": "tan_accelerator", "tanning_mechanism": "Maillard_reaction", "color_development_onset_hours": "0.0", "full_color_development_hours": "0", "color_duration_days": "0", "DHA_concentration_if_applicable_pct": "0", "erythrulose_concentration_pct": "0", "pH_dependent_color": "no", "formaldehyde_release_concern": "no", "formaldehyde_release_ppm": "0", "AGE_fo…

PubChem Annotations

Safety and regulatory annotations from PubChem (NCBI) aggregated sources.

Safety (2)
Carcinogen Classification
No indication of carcinogenicity to humans (not listed by IARC).
Source: Toxin and Toxin Target Database (T3DB)
Carcinogen Classification
L-tryptophan | TR-071: Bioassay of L-Tryptophan for Possible Carcinogenicity (CASRN 73-22-3) (1978 ) | 03/07/78 | No Evidence | No Evidence | No Evidence | No Evidence | It is concluded that under the conditions of this bioassay, L-tryptophan was not carcinogenic for Fischer 344 rats or B6C3F1 mice.
Source: NTP Technical Reports

Function Categories & List Membership

Cosmetic/Chemical Function Categories
Flavouring and nutrient
Regulatory List Membership (1)
FDA Substances Added to Food (EAFUS)

Expert Verdict

Expert safety assessment and concern-level summary for L-Tryptophan.

Regulatory Flags

amino-acid essential-amino-acid antistatic hair-conditioning masking fda_food_additive

NOAEL Studies Summary

View details ->

Public NOAEL study rows linked to L-Tryptophan by CAS number or substance name.

Studies
9
Lowest NOAEL
400 mg/kg bw/day
Highest NOAEL
7500 mg/kg bw/day
COSMOS_DB

Known Synonyms

(S)-2-Amino-3-(1H-indol-3-yl)propanoic acid Triptophan L-TRYPTOPHAN (AMINO ACID) Alanine, 3-indol-3-yl- L-alpha-Aminoindole-3-propionic acid alpha'-Amino-3-indolepropionic acid alpha-Amino-3-indolepropionic acid, L- EINECS 200-795-6 1H-Indole-3-propanoic acid, alpha-amino-, (S)- Indole-3-propionic acid, alpha-amino- NCI-C01729 Propionic acid, 2-amino-3-indol-3-yl- tryptophan (H-3) UNII-8DUH1N11BX (L)-tryptophan (S)-1H-Indole-3-alanine (S)-a-Amino-1H-indole-3-propanoic acid (S)-a-Aminoindole-3-propionic acid (S)-a-amino-b-indolepropionic acid (S)-alpha-Aminoindole-3-propionic acid

Chemical Function

Flavouring and nutrient

Regulatory Lists

active_ingredient; Europe; Pesticides inert_ingredient; Pesticides inert_ingredient; non_food_use; Pesticides food_additive; Substances Added to Food (formerly EAFUS) (2/2019)

Cross-Vertical Safety Context

Same-CAS public records found in pharmaceutical data.

SOURCE ChEMBL / DrugCentral / FAERS DB_PHARMA CAS match

Pharmaceutical Data

Same-CAS rows from the pharmaceutical spoke database.

Compound
TRYPTOPHAN
ChEMBL ID
CHEMBL54976
Max Phase
4
Adverse Event Associations
18
View full pharmaceutical profile →

Frequently Asked Questions

Is L-Tryptophan safe in cosmetics?

L-Tryptophan has a safety rating of "GOOD" in our database. EU status: permitted. US status: permitted. 9 toxicological study endpoint(s) are available in our database.

Is L-Tryptophan allowed in the EU?

L-Tryptophan EU regulatory status: permitted. This is based on EU Regulation 1223/2009 and its amendments.

What does L-Tryptophan do in cosmetics?

L-Tryptophan functions as: Antistatic, Hair conditioning, Masking. It is classified as a cosmetic ingredient in our database. CAS number: 73-22-3.

What is the NOAEL for L-Tryptophan?

The NOAEL (No Observed Adverse Effect Level) for L-Tryptophan is 400 mg/kg bw/day based on a Short Term Toxicity study via oral route in swine. A total of 9 study endpoints are available. Source: COSMOS_DB.

Is L-Tryptophan used outside cosmetics?

L-Tryptophan also appears in industrial chemical safety and pharmaceutical data. The cross-vertical cards on this page render same-CAS public rows from the matched databases.

Compliance Tools

Check L-Tryptophan compliance across multiple jurisdictions:

Ingredient Decoder
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82 Allergen Checker
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Substance Compliance
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MoS Calculator
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Heavy Metal Limits
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