L-Cysteine-glutathione disulfide, a glutathione derivative endogenous to mammalian cells, is comprised of the oxidized form of free glutathione tripeptide linked via a disulfide bond to L-cysteine. It has been shown to protect mice against acetaminophen-induced hepatotoxicity.

L-Cysteine hydrochloride hydrate (L-Cysteine hydrochloride monohydrate) is a conditionally essential amino acid, which acts as a precursor for biologically active molecules such as hydrogen sulphide (H2S), taurine and glutathione. L-Cysteine hydrochloride hydrate suppresses ghrelin and reduces appetite in rodents and humans.

L-Cysteine (L-(+)-Cysteine) is a non-essential sulfur-containing amino acid in humans. L-Cysteine is important for protein synthesis, detoxification, and diverse metabolic functions. Found in beta-keratin, the main protein in nails, skin, and hair, L-Cysteine is important in collagen production, as well as skin elasticity and texture. Also required in the manufacture of amino acid taurine, L-Cysteine is a component of the antioxidant glutathione, and plays a role in the metabolism of essential biochemicals such as coenzyme A, heparin, and biotin.

S-(N-Methylsulfinylbutylthiocarbamoyl)-L-cysteine (SFN-Cys) is an isothiocyanate derivative, functioning as an active metabolite of sulforaphane, a class I and II histone deacetylase (HDAC) inhibitor, and anticancer agent. This compound is generated from sulforaphane through intermediates - DL-sulforaphane glutathione and sulforaphane cysteinylglycine - via the mercapturic acid pathway enzymes. At a concentration of 20 µM, SFN-Cys diminishes invasion and migration of U87MG and U373 MG glioblastoma cells as observed in wound healing and chamber assays. Furthermore, at 45 µM, it significantly lowers the expression of α-tubulin, βIII-tubulin, stathmin 1, and X-linked inhibitor of apoptosis (XIAP), and also reduces cell density in paclitaxel-resistant A549 lung cancer cells (A549/T). Additionally, when used at 30 µM, SFN-Cys prompts apoptosis and cell cycle arrest at the G2/M phase in U87MG and U373 MG cells.

Ophthalmic acid is a glutathione analog in which cysteine is substituted by L-aminobutyrate.

D-Ribose-L-cysteine is the antioxidant glutathione precursor.

L-Cysteine-d3 is a deuterated compound of L-Cysteine. L-Cysteine has a CAS number of 52-90-4. L-Cysteine is a non-essential sulfur-containing amino acid in humans. L-Cysteine is important for protein synthesis, detoxification, and diverse metabolic functions. Found in beta-keratin, the main protein in nails, skin, and hair, L-Cysteine is important in collagen production, as well as skin elasticity and texture. Also required in the manufacture of amino acid taurine, L-Cysteine is a component of the antioxidant glutathione, and plays a role in the metabolism of essential biochemicals such as coenzyme A, heparin, and biotin.

Glutathione oxidized (L(-)-Glutathione) is a GLUTATHIONE dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized.

Glutathione can occur in reduced (GSH), oxidized (GSSG), or in mixed disulfide forms and is ubiquitous in multiple biological systems serving as the major thiol-disulfide redox buffer of the cell. GSSG is the oxidized form of GSH . It can be reduced back to GSH through the NADPH-dependent enzyme glutathione reductase. GSSG functions as a hydrogen acceptor in the enzymatic determination of NADP+ and NADPH and can be a proximal donor in S-glutathionylation post translational modifications. The ratio of reduced glutathione to oxidized glutathione within cells is often used as an indicator of oxidative stress, with higher concentrations of GSSG predicting increased oxidative stress.

D-Cysteine is the D-isomer of cysteine and a powerful inhibitor of the growth of E. coli. D-cysteine is mediated by D-amino acid oxidase to produce H2S, and is a neuroprotective agent against cerebellar ataxia. D-cysteine can inhibit the growth and cariog

Cysteine monohydrate is a semi-essential proteinogenic amino acid.

Cysteine hydrazide is an enrichment tool for the mass spectrometric characterization of bacterial-free oligosaccharides.