Where it comes from: Tyrosine is an amino acid, a building block of protein. "Tyrosine is processed in the body from phenylalanine—another amino acid," explains Barbie Broschart, RD and a nutritional counselor. Tyrosine is made in our bodies and is also found naturally in animal protein (chicken, fish, turkey, eggs, cheese, milk) and plant protein (nuts, seeds and some beans).
What it'll do for you: "Tyrosine is the building block for several important neurotransmitters, including epinephrine, norepinephrine, serotonin, and dopamine." It is also a component for making melanin (the pigment for hair and skin) and aids in organ function responsible for processing regulating hormones. Because of tyrosine's key role with certain neurotransmitters, which govern mental alertness in the brain—epinephrine and dopamine—tyrosine may help with alertness in those who have not slept, but more research is needed," Broschart says.
Tyrosine is also involved in the production of the stress hormones epinephrine and norepinephrine. Some experts believe that, under stress, the body isn't able to make enough tyrosine. A handful of animal and human studies suggest that tyrosine supplements may help improve memory and performance under psychological stress—making the amino acid of particular interest to the military. In one study, 21 cadets in the Netherlands were put through a demanding one-week military training course. Ten cadets were given a drink with two grams of tyrosine a day, while the other cadets were given an identical drink without tyrosine. Those who drank the tyrosine were better at memorizing tasks and tracking the tasks they had done.
Tyrosine supplements are often marketed as an anti-depressant, again, because of tyrosine's role in producing dopamine and serotonin. (Those who are depressed have been known to show low levels of each). However, tyrosine may cause a severe increase in blood pressure in people taking certain antidepressant medications. Be sure to talk to your doctor before self-prescribe anything—especially if you're already taking medicines on a regular basis.
Suggested intake: "Most health professionals recommend around 500-1000 mg three times per day before each meal," Broschart says before adding (again!): "You should contact your health professional or nutritionist before using."
Tyrosine is found naturally in soy products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds and sesame seeds.
Tyrosine deficiencies are rare—especially for men eating a balanced diet. Low levels have been associated with low blood pressure, low body temperature and an underactive thyroid. However, tyrosine supplements have not been found to improve any of these conditions.
Associated risks/scrutiny: Taking too much tyrosine could cause gastrointestinal issues like nausea and vomiting, migraines. People who take medication for thyroid problems, depression, or Parkinson's disease should not supplement with tyrosine.