Cysteine

Summary

Cysteine (CHEMBL863) is an approved small-molecule flour treatment agent; indicated across 2 conditions including uremia and vitamin d deficiency.

At a glance

• Status: Approved (max clinical phase 4)
• Modality: Small molecule
• Indications: 2 conditions
• Clinical trials: 11
• Chemistry: 121.16 Da · C3H7NO2S

Identifiers

Drug identity and classification

Field	Value
ChEMBL ID	CHEMBL863
Name	Cysteine
Type	Small molecule
Max phase	4
FDA approved	yes
PubChem CID	5862
ChEBI	CHEBI:17561
Molecular formula	C3H7NO2S
Molecular weight	121.16
InChIKey	XUJNEKJLAYXESH-REOHCLBHSA-N

SMILES: C([C@@H](C(=O)O)N)S

IUPAC name: (2R)-2-amino-3-sulfanylpropanoic acid

ChEBI definition: An optically active form of cysteine having L-configuration.

Pharmacological roles (ChEBI): flour treatment agent, EC 4.3.1.3 (histidine ammonia-lyase) inhibitor.

Other ChEBI roles (chemical / environmental): human metabolite.

Also known as: Cisteina, Cysteine, Cysteinum, E 920, E920, E921, FEMA NO. 3263, L-cysteine, NSC-8746, cysteine, L-Cys, L-Cystine

Parent form; salt/anhydrous children: CHEMBL1200630

Patent coverage: 237,966 distinct patent families (733,144 SureChEMBL compound mentions), from 1 matched compound structure(s). Mentions count patents naming the compound (not distinct inventions), so promiscuous / reference molecules inflate the mention figure — families are the dedup metric.

Targets

Targets

Broader ChEMBL bioactivity targets: 2 (assay-derived). Sample: Cystine/glutamate transporter, Prostaglandin G/H synthase 1.

Bioactivity

ChEMBL activities: 1 potent at pChembl ≥ 5 of 2 total. Top 30 by potency (10 = 0.1 nM, 6 = 1 µM):

Target	pChembl	Type	Value	Unit	Activity ID
PTGS1	5.33	AC50	4657	nM	CHEMBL_ACT_25205929

Target pathways

No target-pathway data for this drug (no mapped target genes).

Indications & clinical

Indications

2 indications (0 at ChEMBL trial phase 4). Phase below is the highest clinical-trial phase recorded for this drug against each disease — not the molecule’s overall approval status (that is in the Summary).

Indication	Trial phase	MONDO	EFO
uremia	2	MONDO:0007008	EFO:1001226
vitamin D deficiency	0	MONDO:0100471	EFO:0003762

Clinical trials

Total trials: 11.

Phase distribution

Phase	Trials
Not specified	4
PHASE2	2
PHASE1	2
EARLY_PHASE1	2
PHASE3	1

Top trials by phase / activity

NCT	Phase	Status	Title
NCT01820195	PHASE3	UNKNOWN	N-Acetyl Cystein and Contrast Nephropathy
NCT02050139	PHASE2	COMPLETED	L-Cysteine in Peritoneal Dialysis
NCT02524262	PHASE2	COMPLETED	L-cysteine Prevents Stomach Exposure to Carcinogenic Acetaldehyde
NCT01355198	PHASE1	COMPLETED	Role of HIV on Glutathione Synthesis and Oxidative Stress
NCT02462746	PHASE1	COMPLETED	The Effect of Cysteine, Tryptophan and Tyrosine Supplements on Breast Milk
NCT02937376	EARLY_PHASE1	UNKNOWN	Effects of N-acetyl Cystein (NAC) Supplementation in G6PD Deficient Individuals After Acute Exercise
NCT04939792	EARLY_PHASE1	COMPLETED	Optimization of Blood Levels of 25(OH)-Vitamin D in African Americans
NCT06622577	Not specified	NOT_YET_RECRUITING	The Effect of Dietary Management and Cysteine Supplementation on Growth Parameters and Biochemical Control for Pediatric Qatari Patients Affected with Classical B6 Non-responsive Homocystinuria.
NCT03180775	Not specified	UNKNOWN	Effects of Dietary Amino Acids on Serum and Macrophage Atherogenicity
NCT04923555	Not specified	COMPLETED	Analysis of the Postprandial Effects of a Vegetable Protein Mixture Rich in Arginine, Cysteine and Leucine on Endothelial Dysfunction and Inflammation at Low Noise in Elderly People With Cardiometabolic Risk
NCT07553520	Not specified	WITHDRAWN	Dietary Cysteine and Methionine Deprivation (CMD) in Glioma Patients

Clinical evidence (CIViC)

No CIViC predictive evidence (expected for non-precision-medicine drugs).

Pharmacology

Pharmacogenomics

No CPIC/DPWG dosing guideline or drug-level clinical/variant annotations in PharmGKB for this molecule.

Related molecules

Related molecules

No competitor molecules sharing a primary target (ChEMBL phase ≥2 or PubChem drug-class).