Tyrosine is one of the 20 amino acids that are used by cells to synthesize proteins, but studies have also shown that it may reduce stress, improve memory, and lower blood pressure even when the subject is feeling tense, all of which aids in generating a healthy metabolism. It is a building block for several neurotransmitters that affect mood. Additionally, some scientists have found that tyrosine may affect thyroid hormone levels in such a way that boosts metabolism. To get more tyrosine in your diet, dine on foods such as turkey, fish, chicken, nuts, and dairy products. If you choose to take a supplement, ingest it a half hour before meals and with a multivitamin-mineral complex that will help break it down into the chemicals you need. Be careful though. Tyrosine may cause a severe blood pressure increase in people taking the antidepressant medications known as MAOIs. It may also raise thyroid levels when taken with synthetic thyroid hormones. No one should take tyrosine at the same time as levodopa, a Parkinson’s drug. Be sure to consult your physician before starting, or radically changing, any physical, nutritional, or supplemental regimen.