• Chemical Name:L-Cystine
  • CAS No.:56-89-3
  • MF: C6H12N2O4S2
  • MW:240.3
  • Purity:>98% or As customer requested
  • Color:White
  • Product Categories:Biochemistry;Nutritional Supplements;L-Amino Acids;Amino Acids; APIs; Biochemical Engineering
  • Test method: HPLC


What is Cystine? 

Not considered one of the 20 amino acids, Cystine is a sulfur-containing derivative obtained from oxidation of cysteine amino acid thiol side chains. It functions as an antioxidant and protects tissues against radiation and pollution, slowing the aging process. It also aids protein synthesis. Cystine is abundant in many proteins of skeletal tissues and skin, and found in insulin and digestive enzymes chromotrypsinogen A, papain, and trypsinogen. (Source: NCI Thesaurus (NCIt))

Basic information 

Product Name: L-Cystine
Synonyms: cystine; L-Cystin; Cystine acid; L-Dicysteine; Dicysteine; Gelucystine; L-Cystine 99%
CAS: 56-89-3
MF: C6H12N2O4S2
MW: 240.3
EINECS: 200-296-3
Product Categories: Biochemistry;Nutritional Supplements;L-Amino Acids;Amino Acids; APIs; Biochemical Engineering
Chemical Structure


Chemical Properties


Melting point  >240 °C (dec.) (lit.)
alpha  -224 º(c=2 in 1M HCl)
Boiling point  468.2±45.0 °C(Predicted)
density  1.68
refractive index  -222.5 ° (C=1, 1mol/L HCl)
storage temp.  2-8°C
solubility  1 M HCl: 100 mg/mL
form  Powder/Solid
pka 1.0, 2.1, 8.02, 8.71(at 25℃)
color  White
optical activity [α]20/D 219±5°, c = 1% in 1 M HCl
Water Solubility  0.112 g/L (25 ºC)
Merck  14,2782
BRN  1728094
Stability: Stable. Incompatible with strong oxidizing agents.
Usage And Synthesis

Chemical Properties: A white or almost white, crystalline powder, practically insoluble in water and in alcohol.    

Cystine Uses

L-Cystine is a non-essential amino acid for human development. L-Cystine is formed by the dimerization of two cysteines through the sulfur.    

Technical Support & Resources

Information provided in the product description is from published literature. Due to the nature of scientific experimentation, your results (e.g., selectivity and effective concentrations) or specific application for this product may differ. If you have questions about how this product fits your application, please contact our technical support staff.

MSDS: MSDS available.

COA: COA can be available if you send us inquiry.

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