Molekula
L-Cysteine
Supplying 4,500+ customers in over 80 countries
ISO 9001:2015 & ISO 14001:2015 certified · Supplying laboratories and industry since 2000 · Listed pack sizes are a starting point — we manufacture, source and repack to the quantity you need
L-Cysteine is a sulfur-containing amino acid used in biochemical research, pharmaceuticals, and food supplements for its role in protein synthesis and antioxidant activity. In food manufacturing it serves as a flour treatment agent and dough conditioner for bread, and it is also used as a flavoring ingredient. It is available as a white to off-white crystalline powder. CAS: 52-90-4, Molecular Formula: HSCH2CH(NH2)CO2H, Molecular Weight: 121.16 g/mol. Store at 2 to 8 °C. Signal word: Warning. Molekula supplies L-Cysteine from research to bulk quantities with full documentation and ISO 9001:2015 traceability.
Example image for illustration only. Other packaging and pack sizes are available.
Pricing & pack sizes
These pack sizes aren't a limit. Molekula manufactures, sources and repacks to order — if you need 500 kg and only see 1 kg listed, . We quote from grams to multi-tonne.
Need a different size? Add the nearest pack and change the size in your basket — we price it at the same rate per unit.
-
100 g — £38.90 per pack ex VAT · £46.68 inc. VAT
-
1 kg — £185.50 per pack ex VAT · £222.60 inc. VAT
Need a different quantity or pack?
Tell us how much you need and when — drums, IBCs, sacks or a one-off bulk lot. We'll manufacture or source it and come back with a price.
Prices exclude VAT/sales tax and shipping.
Specifications
| Property | Value |
|---|---|
| Appearance | White crystalline powder |
| Specific rotation | +8.3° to +9.5° |
| pH | 4.5 - 5.5 |
| Loss on Drying | ≤ 0.5% |
| Chloride (Cl-) | ≤0.2% |
| Assay | 98.0 - 101.0% |
| Residue on Ignition | ≤ 0.1% |
| Heavy Metals (Pb) | ≤ 10ppm |
| Iron (Fe) | ≤ 10ppm |
| Arsenic trioxide (As2O3) | ≤ 1ppm |
| Ammonium (NH4+) | ≤ 0.02% |
| Sulphates (SO4)(2-) | ≤ 0.03% |
| State of Solution | ≥ 95.0% |
| Identification (RAMAN) | Conforms to Reference |
Storage & handling
| Property | Value |
|---|---|
| Storage Temperature | 2 to 8 °C |
| Acidity | Neutral |
Literature values
Published physical properties of the substance, not batch specifications.
| Property | Value |
|---|---|
| Appearance | Colorless crystals |
| Melting Point | 260 °C decomposes |
| Water Solubility | Freely soluble in water |
| Solubility (other solvents) | Very soluble in water and acetic acid; Insoluble in ether, acetone and benzene |
| Vapour Pressure | 0.00000207 mmHg |
| pKa | pKa = 1.71 |
| log P (octanol/water) | -2.49 |
Source: PubChem CID 5862 (HSDB, Joint FAO/WHO Expert Committee on Food Additives (JECFA), Haz-Map, DrugBank)
Identification
| Property | Value |
|---|---|
| SKU | 15386031 |
| CAS Number | 52-90-4 |
| IUPAC Name | (2R)-2-amino-3-sulfanylpropanoic acid |
| EC Number | 200-158-2 |
| Molecular Formula | HSCH2CH(NH2)CO2H |
| Molecular Weight | 121.16 |
| Exact Mass | 121.0197 |
| SMILES | C([C@@H](C(=O)O)N)S |
| InChIKey | XUJNEKJLAYXESH-REOHCLBHSA-N |
| InChI | InChI=1S/C3H7NO2S/c4-2(1-7)3(5)6/h2,7H,1,4H2,(H,5,6)/t2-/m0/s1 |
| PubChem CID | 5862 |
| REACH Code | Y110 |
| TSCA Listed | Yes |
| HTS Code | 29309092 |
| Tariff Code | 2930901300 |
Safety & GHS
-
Health Hazard
GHS07
Hazard statements
- H302 Harmful if swallowed
Precautionary statements
- P264 Wash thoroughly after handling
- P280 Wear protective gloves/protective clothing/eye protection/face protection
- P301+312 IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell
- P305+351+338 IF IN EYES: Rinse with water for several minutes. Remove contact lenses if present and easy to do. Continue rinsing
Documents
Safety Data Sheets (SDS)
Available in English, French, German, Italian, Portuguese, Spanish.
Certificate of Analysis (CoA) by batch
Enter a lot or batch number to retrieve the CoA for that specific batch. We can generate one from spec data if no PDF is on file.
Synonyms
- (2R)-2-amino-3-sulfanylpropanoic acid
- (R)-2-Amino-3-mercaptopropanoic acid
- beta-Mercaptoalanine
- Cystein
- cysteine
- Cysteinum
- Half-cystine
- L-Cys
- L-Cystein
- Thioserine
Frequently asked questions
What is L-Cysteine used for?
L-Cysteine is used in pharmaceuticals, cosmetics, and food additives as a reducing agent and antioxidant, and in the synthesis of other chemicals.
What is the chemical formula and molecular weight of L-Cysteine?
The formula is HSCH2CH(NH2)CO2H and the molecular weight is 121.16 g/mol.
How should L-Cysteine be stored?
Store at 2 to 8 °C in a cool, dry place, protected from light and moisture.
What grade of L-Cysteine does Molekula supply?
Molekula supplies L-Cysteine in pharmaceutical and research-grade purity.
Can Molekula supply L-Cysteine in bulk?
Yes, Molekula can supply L-Cysteine in bulk quantities—please contact sales for details.
What documentation comes with an order of L-Cysteine?
Each order includes a Certificate of Analysis (CoA) and safety data sheet (SDS) with the shipment.
Ready to order or need a custom pack?
Tell us the product, grade, and quantity — Molekula usually responds within one working day with pricing and lead time.