N-acetyl-L-cysteine (NAC) (NAC)

N-acetylcysteine (NAC) is a derivative of the sulfur-containing amino acid L-cysteine and serves as a critical precursor for the synthesis of glutathione (GSH), the body's primary endogenous antioxidant (PubChem, CID 12035). While often categorized as a drug or dietary supplement rather than a classical therapeutic target, NAC is central to redox homeostasis and cellular detoxification (StatPearls, NBK537183). Its primary clinical roles include serving as the gold-standard antidote for acetaminophen overdose by replenishing hepatic GSH and acting as a mucolytic agent in respiratory diseases by cleaving disulfide bonds in mucins (Wikipedia, Acetylcysteine). Beyond these established uses, NAC is increasingly investigated for its ability to modulate glutamatergic signaling via the cystine-glutamate antiporter (System xc-) and its anti-inflammatory effects through the inhibition of NF-κB (PMC, PMC3044191). Its multifaceted mechanism of action makes it a versatile tool in treating conditions ranging from chronic bronchitis to neuropsychiatric disorders characterized by oxidative stress and glutamate dysregulation (PMC, PMC5241507).

Other names

AcetylcysteineN-acetylcysteineL-alpha-acetamido-beta-mercaptopropionic acidMercapturic acidMucomystAcetadoteParvolex

N-acetylcysteine acts as a prodrug for L-cysteine, which is the rate-limiting substrate for the synthesis of the antioxidant glutathione (GSH). It also possesses a free thiol group that directly scavenges reactive oxygen species and reduces disulfide bonds in mucoproteins, thereby decreasing mucus viscosity. Additionally, it modulates the cystine-glutamate antiporter (System xc-), increasing extracellular glutamate levels and influencing glutamatergic neurotransmission.