Excessive free radical formation and depletion of the brain's primary antioxidant, glutathione, are established components of Parkinson's disease (PD) pathophysiology. While there is rationale for the therapeutic use of reduced glutathione (GSH) in PD, and even some preliminary evidence to suggest the use of GSH can lead to symptomatic improvement, obstacles surrounding currently employed delivery methods have hindered the clinical utility of this therapy. Intranasal GSH, (in)GSH, is a novel method of delivery for this popular CAM therapy in patients with PD, and bypasses the obstacles associated with other delivery methods. It has been used in clinical practice since 2005. The aim of this study is to evaluate safety, tolerability, and preliminary absorption data of (in)GSH in volunteers with PD in a Phase I single ascending dose escalation study.

Individuals will be randomized to one of three treatment (100 mg GSH/ ml, 200 mg GSH/ ml, or placebo) arms in a double-blind fashion. All study medication will be administered 1 ml three times daily for three months, with a one-month wash out.

Inclusion Criteria:

1. Diagnosis of Parkinson's Disease made by neurologist within previous 10 years
2. Modified Hoehn and Yahr Stage <3
3. Age >20
4. Subjects must be able to attend study visits at screening, baseline, weeks 4, 8, 12, 16
5. Subjects must be able to demonstrate self-administration of study medication or have active caregiver who can administer daily.
6. Dose and frequency of all pharmaceutical medications must be stable for one month prior to enrollment.
7. Diet, exercise and supplementation must be kept constant throughout participation in study
8. Ability to read and speak English

Exclusion Criteria:

1. Dementia as evidenced by Montreal Cognitive Assessment (MoCA) <24
2. Diseases with features common to Parkinson's Disease (eg. essential tremor, multiple system atrophy, progressive supranuclear palsy)
3. Epilepsy
4. History of stroke, CVA
5. Elevated levels of ALT, AST, BUN or creatinine
6. Chronic sinusitis as defined by SNOT-20 score >1.0 on items 1-10.
7. Presence of other serious illness
8. History of brain surgery
9. History of structural brain damage
10. History of intranasal telangiectasia
11. Supplementation with glutathione and agents shown to increase glutathione will not be permitted and will require a 90 day washout period.
12. Pregnant or at risk of becoming pregnant.