Used as an inhalant N-Acetyl Cysteine may treat certain respiratory conditions such as asthma as well as cystic fibrosis. It is a byproduct of glutathione, a substance made from glutamic acid, amino acids glycine and cysteine. Glutathione is responsible for many important bodily processes, notably building and repairing tissue and is produced in the liver. N-Acetyl Cysteine helps to replenish and regulate glutathione in the body. Ultimately, N-Acetyl Cysteine plays an important role in brain heath and may treat some conditions such as Parkinson's and Alzheimer's diseases.