Does N-acetylcysteine affect Parkinson’s disease?

Parkinson’s disease is characterized by the progressive loss of dopamine-producing neurons in the brain and is associated with increased levels of oxidative stress and a relative depletion of glutathione in brain tissue.^[1] N-acetylcysteine (NAC) reliably increases glutathione levels in the body, and preclinical and preliminary clinical research has pointed to a possible therapeutic effect of NAC in Parkinson’s disease.

In two small studies, people with Parkinson’s disease who received NAC for 3 months demonstrated increased dopamine functioning in the brain (determined by a brain scan done before and after the intervention which measured dopamine transporter binding) alongside reduced disease symptoms compared to a control group. NAC was given as a weekly intravenous infusion (50 mg per kg of body weight) in addition to daily oral NAC (1,000 to 1,200 mg). The control groups received standard care, but no placebo, which could bias these findings in favor of NAC.^[2]

It’s important to note that while intravenous NAC does appear to increase glutathione levels in the brain, NAC taken orally (6,000 mg daily) has not currently been found to have this effect in humans. Currently, there’s no evidence in humans that oral NAC alone can improve Parkinson’s disease.^[3][4]