h-l-Cystine
CAS 56-89-3
EC 200-296-3
Formula C6H12N2O4S2
MW 240.3 g/mol
Amino Acids & Peptides Personal Care & CosmeticsPharmaceuticals & HealthcareFood & Nutrition Humectant & MoisturizingAntioxidant & StabilizerpH Regulation & Buffering
Description
H-L-Cystine (CAS 56-89-3), also known as L-Cystine or (CYS)2, is a naturally occurring dimeric amino acid formed by the oxidative coupling of two L-cysteine molecules via a disulfide bond. It carries no assigned E-code and is distinct from its monomeric counterpart in both structure and functional behaviour.
In personal care formulations, L-Cystine acts as a hair and skin conditioner by contributing sulfur-containing bonds that support keratin structure integrity, while its reducing capacity helps regulate disulfide exchange in permanent wave and straightening systems. In food and pharmaceutical applications, it functions as a humectant and pH buffer, stabilising moisture levels and moderating acidic drift in sensitive formulations.
L-Cystine is available in pharmaceutical-grade (Ph.Eur.) and food-grade (FCC) specifications, supporting compliance across EU cosmetic, food, and medicinal product frameworks. It is subject to REACH registration and supplied as a white crystalline powder in standard bulk packaging formats suited to industrial procurement.
In personal care formulations, L-Cystine acts as a hair and skin conditioner by contributing sulfur-containing bonds that support keratin structure integrity, while its reducing capacity helps regulate disulfide exchange in permanent wave and straightening systems. In food and pharmaceutical applications, it functions as a humectant and pH buffer, stabilising moisture levels and moderating acidic drift in sensitive formulations.
L-Cystine is available in pharmaceutical-grade (Ph.Eur.) and food-grade (FCC) specifications, supporting compliance across EU cosmetic, food, and medicinal product frameworks. It is subject to REACH registration and supplied as a white crystalline powder in standard bulk packaging formats suited to industrial procurement.
Physical Properties
| Melting Point | 260.5 °C (decomp) |
| Boiling Point | 468.2±45.0 °C(Predicted) |
| Density | 7.8 g/cm³ |
| Appearance | White crystalline powder |
| Color | White |
| Form | Powder/Solid |
| Water Solubility | 0.112 g/L (25 ºC) |
| Refractive Index | -222.5 ° (C=1, 1mol/L HCl) |
| pH | 4.60 |
| Log P | 0.773 (est) |
Trade & Regulatory
| HS Code | 29309014 |
| Storage Class | 11 - Combustible Solids |
| WGK (Germany) | 3 |
Other Names
cystineL-Cystine(-)-cystine(CYS)2Dicysteine(H-CYS-OH)2
Related Products
Raw Materials
Derivatives
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