NAC - N-Acetyl Cysteine Donate Fundraise NAC (N-Acetyl Cysteine) is a readily available health supplement In its clinical strength it is used to treat paracetamol overdose and to loosen thick mucous in conditions like Cystic Fibrosis NAC works by increasing the levels of an amino acid called cysteine available to the brain, which in turn increases the amount of a major antioxidant called glutathione - this, it is believed, helps to reduce neuronal death Past research has shown that people with Parkinson's have reduced levels of glutathione - we hypothesise that by using NAC to increase levels of glutathione in the brain, we can reduce neuronal death and slow down the progression of Parkinson's This trial will be led by Professor Caroline Tanner and will take place across multiple centres in California, US. FUNDING IS STILL NEEDED FOR THIS TRIAL