NAC (N-acetylcysteine)
NAC is the substance from which amino acids glutathione and L-cysteine are formed. Taking NAC supplements has been associated with an increase in glutathione [17] levels in the body. This glutathione is a powerful antioxidant [18] that plays a critical role in regulating inflammation and combatting oxidative damage.
According to research [19], depressed people tend to have higher levels of inflammatory cytokines. It is thought that NAC may help reduce inflammation and improve depression symptoms. It may also help improve neurotransmitter dysregulation present in people with psychiatric disorders like schizophrenia and mood disorders like depression. NAC supplements of 2 to 2.4 grams daily may help treat these disorders.
A review of five studies [20] found that treatment with NAC was more effective than placebos and help improve symptoms of depression in participants. While more studies are needed, this review found that NAC supplements were safe for consumption.