The investigators are observing the effects 2,000 mg of L-tyrosine will have on 24 hour blood pressure fluctuations in individuals with Parkinson's disease.

We will be monitoring 24 hour ambulatory BP and HR in subjects with PD on 3 separate visits. The first visit will be without an intervention to establish a baseline of 24 hour BP fluctuations. One week later the subject will be given either L-tyrosine (2,000 mg) with B6 (10 mg) or a sugar pill. We will monitor 24 hour BP and HR after supplementation. One week later the subject will repeat the same procedures with either supplement or placebo.

This is a total of 3 visits with 24 hour ambulatory BP and HR monitoring.

Inclusion Criteria:

1. All subjects must have a diagnosis of PD by a licensed neurologist according to the UK Parkinson's Disease Society Brain Bank Clinical Diagnostic Criteria (UKPDBB).(Goetz, 2010) The UKPDBB is a 3 step diagnostic tool which defines inclusion and exclusion criteria for diagnosing PD
2. between 35 and 79 years of age
3. mentally able to participate in the study

Exclusion Criteria:

1. Pregnancy
2. any person who is currently taking amino acid supplements.
3. Any history of myocardial infarction, stent, or CABG
4. Phenylketonurics
5. Untreated hypertension