Tyrosine: Uses, Sources, Benefits and Side Effects

Tyrosine is one of 20 amino acids that are vital for good health. Without it, your body wouldn't be able to make key chemicals, which would affect things like your mood, appetite and even your skin pigment.

L-tyrosine is one form of tyrosine, but the two terms are often used interchangeably.

While tyrosine supplements are out there, most people easily get enough from their diets, says Matt Malachowski, PharmD, director of pharmacy for Population Health and Ambulatory Care at Ochsner Health.

Here's what to know about tyrosine, how your body makes it and how supplements may affect various health conditions.

The 20 amino acids in our bodies come together in different combinations to make different bodily components, per the National Library of Medicine.

"Think of amino acids as lego pieces," Malachowski says. "Your body is going to use that lego to make larger molecules like a pirate ship or a castle." Or, in this case, your skin, nails, muscles and brain.

Tyrosine is considered a "nonessential" amino acid, which means that your body makes tyrosine on its own, from another amino acid called phenylalanine, explains Carol Haggans, RD, scientific and health communications consultant with the Office of Dietary Supplements at the National Institutes of Health. Phenylalanine is found in most protein foods (think: meat, fish, dairy, beans).

Tyrosine is used by your body to make dopamine, epinephrine and norepinephrine, Haggans says, all of which are chemical messengers in the brain that help regulate things like your mood, appetite, alertness and concentration.

The amino acid also helps your body make the hair and skin pigment melanin, as well as certain enzymes and thyroid hormones, according to Mount Sinai.

Your body may make enough tyrosine, but you can also find it in lots of foods. According to Mount Sinai, foods high in tyrosine include:

• Avocados
• Almonds
• Bananas
• Cheese and other dairy products
• Fish
• Lima beans
• Red meat
• Peanuts
• Poultry
• Sesame and pumpkin seeds
• Soy products

Because most people's bodies are able to make tyrosine, you don't typically need to worry about getting a certain amount each day from food. But if you want to break it down, the recommended daily intake for tyrosine and phenylalanine combined is 11 mg per pound of body weight, according to the World Health Organization. So, for example, a 150-pound person would aim for 1.65 g total daily.

If you're only eating tyrosine and avoiding phenylalanine, you should aim for the full 11 mg per pound of body weight to come from tyrosine, per the USDA.

It may be easier to think in terms of the recommended daily allowance for protein, says Haggans, because tyrosine is found in protein-rich foods. The RDA for protein is 0.8 grams for every kilogram (2.2 pounds) you weigh, according to Harvard Health Publishing. So the same 150-pound person should aim for about 55 grams of protein daily.

Overall, there's little evidence to support using tyrosine supplements. But that doesn't mean people ‌aren't‌ using them or that companies aren't touting them to help with a slew of health conditions, including depression, anxiety, insomnia and attention deficit hyperactivity disorder (ADHD).

Here's where the research stands on different conditions:

This area may have the most research behind it.

"A couple of studies show that tyrosine supplements might help with memory and cognitive function in people who are stressed," says Haggans, including those who are sleep-deprived.

Two relatively recent review articles, one from November 2015 in the ‌Journal of Psychiatric Research‌ and the other from July 2015 in ‌Military Medicine‌, conclude there's only limited evidence to suggest tyrosine could enhance memory and cognitive function under stress. Nor was there much data to support using tyrosine supplementation to improve physical performance.

To be clear, though, "the studies aren't definitive and more research is needed," says Haggans.

Studies looking at the effect of tyrosine supplementation on other health conditions are even weaker.

‌ADHD:‌ Because tyrosine helps form the neurotransmitters in your brain that control alertness and concentration, some people believe in taking tyrosine for ADHD. But it doesn't seem to be that straightforward. "A few small studies don't show that it's helpful," says Haggans. That includes one 2009 article that stated there was "no evidence" for any benefit in the treatment of ADHD symptoms. Naturally, then, there's no suggested tyrosine dosage for those with ADHD.

‌Depression:‌ Evidence is similarly lacking to suggest tyrosine might help with depression, which is not surprising given the complexity of the condition. "The biochemistry of our bodies is more complicated than to think we can simply eat something that is a precursor [to neurotransmitters involved in mood] and, voila, end up with more of the end product," says Anne Andrews, PhD, professor of psychiatry, biobehavioral sciences, chemistry and biochemistry at UCLA.

‌Insomnia:‌ The authors of one study (conducted almost a decade ago) found some improvement in sleeplessness among 83 detoxified people with a heroin addiction with a combination treatment including tyrosine. But this is an old study in a very specific population, and it's difficult to say how much of a role tyrosine played because of the other treatment factors. So we can't say for sure whether tyrosine helps with sleep.

‌Phenylketonuria:‌ People with a genetic condition called phenylketonuria (PKU) can't metabolize phenylalanine, which means they can't turn it into tyrosine. This can lead to a tyrosine deficiency, so tyrosine supplements may seem like a good solution, but studies haven't shown a benefit of these supplements for people with PKU, per a January 2021 paper in the Cochrane Database of Systematic Reviews.

‌Physical performance:‌ Amino acid supplements like tyrosine, at least based on the research so far, don't seem to play a role in enhancing physical abilities, including bodybuilding. Another word of warning: "Supplements promoted for weight loss, bodybuilding or sexual enhancement are more likely than others to have contamination issues," says Haggans. In other words, they may contain potentially toxic ingredients or substances. What's more, there's no evidence that tyrosine gives you energy; in fact, tiredness is a known side effect of tyrosine supplements (more on that below).

‌Weight loss:‌ It's tempting to look for anything that can help with shedding pounds. But, says Andrews, "There's not enough evidence to say that supplements will help with weight loss," and that includes tyrosine supplements.

Studies have looked at tyrosine supplements for adults at doses up to about 150 mg/kg (that's about 14 grams/day for someone weighing 200 pounds, for reference) for up to three months. They've been found to be largely safe within this 90-day time period but, beyond that, their safety is unproven, says Haggans.

Tyrosine supplements have not been well studied in children, and there is no recommended dosage. Do not give your child l-tyrosine or any other supplement without talking to a doctor.

You should also talk to your doctor if you're pregnant or breastfeeding. It's not known whether tyrosine is safe during pregnancy or lactation.

According to the University of Michigan, tyrosine supplements can have the following side effects (although this may not be a complete list):

• Fatigue
• Nausea or upset stomach
• Heartburn
• Headache
• Joint pain

People with hyperthyroidism or Graves disease should not take tyrosine supplements, per Mount Sinai, because they may increase thyroid hormone levels.

Talk to your doctor or pharmacist before taking tyrosine, as the supplement may interact with medications you're taking. According to the University of Michigan and Mount Sinai, those medications include:

• Levodopa (L-dopa)
• Thyroid replacements such as Synthroid and Levothroid
• Monoamine oxidase inhibitors (MAOIs) such as Marplan, Nardil and Parnate