Cystine Unit Converter

Cystine is the oxidized form of cysteine, created when two cysteine molecules link together through a disulfide bond. It is the predominant form of cysteine circulating in the blood due to its greater chemical stability.

Cystine serves as a reservoir for cysteine, which the body uses to produce glutathione, its primary antioxidant defense molecule. The disulfide bonds formed by cystine also play a critical structural role in proteins like keratin, which gives hair, skin, and nails their strength.

Cystine and cysteine exist in a dynamic balance. The ratio between the two reflects the body's overall oxidative status, with a higher proportion of cystine relative to cysteine suggesting increased oxidative stress.

Cystine forms in the blood when two cysteine molecules oxidize and bond together. Cysteine itself comes from dietary protein (meat, eggs, dairy, legumes) and is also synthesized in the liver from methionine through the transsulfuration pathway.