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.
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.
Function
Antistatic, Hair conditioning, Masking
Editorial assessment
GOOD
Preliminary editorial note — not a computed safety verdict.
Chemistry & Identifiers
IUPAC Name
(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid
InChIKey
QIVBCDIJIAJPQS-VIFPVBQESA-N
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 | EPA ToxRefDB |
| LEL | =1250 mg/kg-day | Rat | oral | chronic | EPA ToxRefDB |
| LEL | =3750 mg/kg-day | Mouse | oral | chronic | EPA ToxRefDB |
| LEL | =3750 mg/kg-day | Mouse | oral | chronic | EPA ToxRefDB |
| LOAEL | >2500 mg/kg-day | Rat | oral | chronic | EPA ToxRefDB |
| LOAEL | >2500 mg/kg-day | Rat | oral | chronic | EPA 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
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)
Editorial summary
Preliminary editorial summary for L-Tryptophan — not a computed safety verdict. See the sourced toxicological data above.
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
Frequently Asked Questions
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
Paste a full ingredient list for instant analysis
82 Allergen Checker
Check for EU declarable fragrance allergens
Substance Compliance
Check compliance across multiple jurisdictions
MoS Calculator
Calculate Margin of Safety using SCCS methodology
Heavy Metal Limits
Compare limits across jurisdictions
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