The Health Benefits of Tyrosine

Tyrosine is an amino acid the body produces from phenylalanine (another type of amino acid). Found in a number of foods including meat, fish, eggs, dairy, eggs, nuts, legumes, and oats, tyrosine is available in dietary supplement form as well.

Tyrosine is essential to your body's production of melanin (a type of pigment) and several key brain chemicals including dopamine and norepinephrine. It also plays an important role in the function of the adrenal, thyroid, and pituitary glands, which are involved in producing and regulating your hormones.

Tyrosine is also commonly known as L-Tyrosine and N-acetyl L-tyrosine (NALT).

One of the most common uses of tyrosine supplements is the treatment of a genetic disorder known as phenylketonuria. In people with phenylketonuria, the body is unable to process phenylalanine properly and, as a result, cannot produce the tyrosine it needs to function.

In alternative medicine, tyrosine supplements are often touted as a natural remedy for a range of health problems, including:

• Alzheimer's disease
• Attention Deficit Hyperactivity Disorder
• Chronic fatigue syndrome
• Depression
• Heart disease
• Parkinson's disease
• Premenstrual syndrome
• Stress
• Stroke

Some alternative medicine proponents claim that tyrosine supplements can also help suppress appetite, promote weight loss, increase mental alertness, improve memory, and enhance athletic performance.

Although relatively few studies have tested the effects of taking tyrosine supplements, there's some evidence that tyrosine may offer certain health benefits. Here's a look at several key findings from the available research:

For a report published in the Cochrane Database of Systematic Reviews in 2013, investigators analyzed the available clinical trials on the use of tyrosine supplements in people with phenylketonuria.

Looking at data from six clinical trials with a total of 56 phenylketonuria patients, the report's authors found that blood levels of tyrosine were significantly higher in participants receiving tyrosine supplements compared to those given a placebo.

However, the authors note that more studies are needed before tyrosine supplements can be recommended for the treatment of phenylketonuria.

Some studies show the use of tyrosine supplements may boost brain function under certain conditions.

A 2010 study published in the Journal of the International Society of Sports Nutrition found that tyrosine supplementation led to significantly greater improvements in focus and alertness after exhaustive exercise. The study included 19 healthy college students, each of whom was given either a tyrosine supplement or a placebo for a four-week period.

In addition, a 2007 study of 19 people published in Physiology & Behavior found that use of tyrosine supplements helped protect against the detrimental effects of severe cold exposure on cognitive performance and memory.

So far, studies examining tyrosine's effects on exercise performance have yielded mixed results.

In a 2011 study from the European Journal of Applied Physiology, for example, tests on eight healthy male volunteers found that consumption of a tyrosine-enriched drink helped increase endurance while exercising in the heat.

However, a 2016 study published in the International Journal of Sports Nutrition and Exercise Metabolism found that tyrosine supplementation failed to protect against exhaustion while exercising in a warm environment.

More research is needed before tyrosine supplements can be recommended for enhanced exercise performance.

Side effects of tyrosine include nausea, heartburn, headache, joint pain, or feeling tired. Though rare, allergic reactions may occur, including hives, difficulty breathing, and tingling and swelling of the face, lips, tongue, or throat. Seek medical attention if an allergic reaction occurs. 

People with hyperthyroidism or Graves disease should not take tyrosine without doctor supervisions, as the body uses tyrosine to make thyroxine, a thyroid hormone.

Tyrosine may interact with the following medications. Speak to your doctor before supplementing if you are taking: 

• MAOI inhibitors, such as the depression medications rasagiline (Azilect), selegiline (Eldepryl, Zelapar), isocarboxazid (Marplan), phenelzine (Nardil), and tranylcypromine (Parnate
• Levodopa, a Parkinson's drug
• Thyroid replacements, such as Synthroid, Levothroid, or other thyroid hormones

It's important to keep in mind that supplements haven't been tested for safety and dietary supplements are largely unregulated. In some cases, the product may deliver doses that differ from the specified amount for each herb. In other cases, the product may be contaminated with other substances such as metals. Also, the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established. 

There is no recommended daily allowance for tyrosine. In research, the following doses have been studied:

• Phenylketonuria: 4 grams to 6 grams a day in food and medical food, or 6 grams to 7.6 grams in pregnant and nursing women, take under doctor supervisions.
• Alertness: 150 mg per kilogram of body weight (mg/kg) split into two doses following the loss of sleep.
• Memory: 150 mg/kg to 300 mg/kg taken prior to a memory task
• Mental Performance: 100 mg/kg to 300 mg/kg taken prior to a stressful mental task.

When selecting a brand of supplements, look for products that have been certified by Consumer Labs, The U.S. Pharmacopeial Convention, or NSF International.

Can tyrosine help me lose weight?

There is no clinical research to show that supplementing with tyrosine can promote weight loss. In theory, it may speed metabolism because it is a precursor to epinephrine, norepinephrine, and dopamine, which is why is it sometimes included in weight-loss supplements.

Does tyrosine cause insomnia?

Tyrosine can be stimulating, especially when used in large amounts, and may boost energy. It should not be taken in the evening as it may interfere with sleep.

Due to the limited research, it's too soon to recommend tyrosine for any condition. It's also important to note that self-treating a condition and avoiding or delaying standard care may have serious consequences. If you're considering using tyrosine for any health purpose, make sure to consult your physician first.