半胱氨酸是氨基酸半胱氨酸和半胱氨酸的氧化产物之一。原毛中的胱氨酸含量通常很低。它随着光化学降解（风化）而增加。漂白或氯化等整理过程总是导致胱氨酸的增加。任何类型氧化的严重程度都可以通过半胱酸的定量测定直接确定。适用于染色前后任何形式的所有羊毛织物，例如松羊毛、条子、竹节、纱线或织物。

Cysteic acid is one of the oxidation products of the amino acids cystine and cysteine. The cysteic acid content of raw wool is normally very low. It increases with photochemical degradation (weathering). Finishing processes such as bleaching or chlorination always result in an increase in cysteic acid. The severity of any kind of oxidation may be determined directly by quantitative determination of cysteic acid. Applicable to all-wool textiles in any form before and after dyeing - for example, loose wool, sliver, slubbing, yarn or fabric.