What is the NOAEL for L-Cysteine?
L-Cysteine has 10 NOAEL studies in the database. The lowest reported value is K848JZ4886 UNII. Source: openFDA substances.
NOAEL Data
REACH Registered
Cosmetic Ingredient
L-Cysteine
Also known as: (2R)-2-Amino-3-sulfanylpropanoic acid, NSC 8746, (R)-2-Amino-3-sulfanylpropanoic acid, Cystein, Cysteine (+15 more)
CAS 52-90-4
L-Cysteine (CAS 52-90-4) is a chemical substance. Key regulatory status: REACH registered, 8 regulatory/inventory lists, cosmetic ingredient cross-reference; source data from EPA ToxValDB, EPA CPDat, ECHA REACH.
SOURCE
noael studies public
NOAEL studies
10
SOURCE
chemical inventory jurisdictions
Regulatory lists
8
SOURCE
eu clp annex vi
GHS signal
Not classified
Chemical Identity
CAS, identifiers, formula, and alternate names for the matched substance record.
SOURCE
DSSTox identifiers
26 fields
Name
L-Cysteine
CAS Number
52-90-4
DTXSID
DTXSID8022876
Molecular Formula
C3H7NO2S
InChI Key
XUJNEKJLAYXESH-REOHCLBHSA-N
Monoisotopic Mass
121.01975
Synonyms
(2R)-2-Amino-3-sulfanylpropanoic acidNSC 8746(R)-2-Amino-3-sulfanylpropanoic acidCysteinCysteinealpha-Amino-beta-mercaptopropanoic acid, L-2-Amino-3-mercaptopropanoic acid, (R)-alpha-Amino-beta-mercaptopropionic acid, L-(R)-2-Amino-3-mercaptopropionic acidalpha-Amino-beta-thiolpropionic acid, L-EINECS 200-158-2FEMA No. 3263
Functional Uses
Industrial and product-use categories associated with this substance.
SOURCE
EPA CPDat
10 records
Flavouring and nutrientProcessing aids not otherwise specifiedFillerFood preservative
Regulatory Lists
Inventory, screening, and regulatory list matches from public chemical databases.
SOURCE
EPA CPDat
8 records
| List | Keyword | Source |
|---|---|---|
| active_ingredient; Australia | Australian Pesticides and Veterinary Medicines Authority | CPCat |
| inert_ingredient; non_food_use; Pesticides | EPA | CPCat |
| pharmaceutical | US International Trade Commission | CPCat |
| children; Europe; Personal care | Danish Environmental Protection Agency | Danish EPA |
| children; Europe; Personal care | Danish Environmental Protection Agency | Danish EPA |
| pharmaceutical | FDA | United States Food and Drug Administration (FDA) |
| Europe | European Commission | Fl@vis |
| food_additive; Substances Added to Food (formerly EAFUS) (2/2019) | FDA | United States Food and Drug Administration (FDA) |
NOAEL Studies
Toxicology endpoints rendered from public NOAEL study rows.
SOURCE
NOAEL studies
Showing 10 of 10 studies
| Value | Unit | Endpoint | Route | Species | Source |
|---|---|---|---|---|---|
| K848JZ4886 | UNII | FDA UNII substance identifier | - | - | openFDA substances |
| K848JZ4886 | UNII | FDA UNII substance identifier | - | - | openFDA substances |
| K848JZ4886 | UNII | FDA UNII substance identifier | - | - | openFDA substances |
| K848JZ4886 | UNII | FDA UNII substance identifier | - | - | openFDA substances |
| =1890 | mg/kg bw | LD50 | oral | Rat | NTP_ICE_acute_oral |
| =7 | mg/kg bw/day | LOEL | injection | Rat | ToxValDB_ECOTOX |
| 100 | mg/kg bw/day | NOAEL | oral | rat | COSMOS_DB |
| 200 | mg/kg bw/day | NOAEL | oral | mouse | COSMOS_DB |
| 3000 | mg/kg bw/day | NOAEL | oral | rat | COSMOS_DB |
| 8000 | mg/kg bw/day | NOAEL | oral | rat | COSMOS_DB |
Showing 10 of 10 studies
REACH Registration
Registration status from the ECHA REACH registered substances database.
SOURCE
ECHA (EU)
1 records
| Status | Name | EC Number | Link |
|---|---|---|---|
| Registered | L-cysteine | 200-158-2 | ECHA overview → |
Cosmetic Safety Profile
Same-CAS cosmetic ingredient record for cross-vertical context.
SOURCE
CosIng / Ingredients DB
EU Status
permitted
Max
-
Category
active
Pharmaceutical Data
Same-CAS pharmaceutical records from drug and bioactivity sources.
SOURCE
EMBL-EBI ChEMBL
CYSTEINE
ChEMBL Phase
4
Adverse Events
18
Bioactivity
5
Food Safety Data
Same-CAS food additive, ADI, and GRAS records where available.
SOURCE
EFSA / FDA GRAS
1 records
ADI: No safety concern at current levels of intake when used as a flavouring agent mg/kg bw
View full food safety profile →Cannabis Data
Same-CAS cannabis compliance and lab records where available.
SOURCE
Cannabis regulatory / lab data
efsa substances
1 cannabis record found in efsa substances.
View full cannabis profile →Frequently Asked Questions
What regulatory lists include L-Cysteine?
L-Cysteine appears on 6 regulatory/inventory lists including active_ingredient; Australia, inert_ingredient; non_food_use; Pesticides, pharmaceutical, and 3 more. Source: EPA CPDat.
Is L-Cysteine used in cosmetics?
Yes, L-Cysteine is also indexed as a cosmetic ingredient under the name L-Cysteine. View the full cosmetic safety profile on the ingredient page for detailed safety data, SCCS opinions, and regulatory status.
Where does the safety data for L-Cysteine come from?
Safety data is sourced from EPA ToxValDB, EPA CPDat, EPA DSSTox, ECHA REACH, CosIng / Ingredients DB, ChEMBL / DailyMed, EFSA / FDA GRAS, cannabis regulatory/lab databases. All data traces to primary regulatory sources and is updated from official government databases.
Is L-Cysteine used outside industrial chemicals?
L-Cysteine also appears in cosmetics, pharmaceutical, food safety, cannabis databases.