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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In vitro studies with L-Cysteine hydrochloride gave inconsistent results. A reverse mutation assays using different strains of Salmonella typhimurium according to Ames a positive response in 2 out of 6 tested strains was observed. In a mammalian cell gene mutation assay using Chinese hamster lung fibroblasts
(V79), genotoxicity of L-cysteine hydrochloride was also positive.
In an in vitro cytogenetic test with human blood cells L-Cysteine HCl was not mutagenic.
In vitro studies on genotoxicity can be classified as screening tests. Therefore some oversensivity seems acceptable. 

Genetic toxicity in vivo

Description of key information

For the evaluation of a genotoxic risk of humans in vivo studies are much more relevant and decicive. An in vivo micronucleus test with mouse bone marrow cells revealed that the substance L-Cysteine hydrochloride is not mutagenic for mammals. Additionally a carcinogenicity test gave no indication of a carcinogenic action of L-Cysteine hydrochloride. The results of these two studies demonstrate, that L-Cysteine hydrochloride is not genotoxic.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Justification for classification or non-classification

For classification and non-classification test results from in vivo studies are relevant. An in vivo micronucleus test with mouse bone marrow cells revealed that the substance L-Cysteine hydrochloride is not mutagenic for mammals. According to Regulation (EC) No.: 1272/2008 and subsequent regulations, the L-Cysteine hydrochloride as well as the monohydrate form is not classified with regard to genetic toxicity.