Can L-Tyrosine Help With ADHD Symptoms?

Woman reading a supplement bottle.

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L-tyrosine is an amino acid that is a precursor (which means it’s necessary for production) to dopamine and norepinephrine, two neurotransmitters that are important for focus and concentration.

According to some research, L-tyrosine has been shown to help improve cognitive performance during times of short-term stress and also improve working memory.

Because of this, the question of whether L-tyrosine may help with attention deficit hyperactivity disorder (ADHD) symptoms has been raised. However, there is limited research on the effectiveness of L-tyrosine for ADHD, and more studies are needed to confirm its efficacy. If you're considering using L-tyrosine for ADHD, talk to your doctor first to see if it's right for you.

Where to Find L-Tyrosine

L-tyrosine is found naturally in many foods, including the following:

  • Eggs
  • Fish
  • Meat
  • Milk
  • Tofu
  • Beans
  • Seeds

L-tyrosine is also available in supplement form. It’s sometimes combined with other ingredients, such as:

  • Vitamins B6: thought to aid in converting L-tyrosine to dopamine
  • Acetyl-L-carnitine: purported to help with mental clarity
  • Folic acid: thought to be beneficial for some with depression

What Chemical Are You Lacking If You Have ADHD

There is no one “chemical” that people with ADHD are lacking. However, some research suggests that ADHD may be associated with a decreased functioning in the neurotransmitters dopamine and norepinephrine (the target of ADHD medications) in certain parts of the brain.

Dopamine and norepinephrine are important neurotransmitters that play a role in focus and concentration. They’re also involved in the “reward center” of the brain, which helps regulate motivation and pleasure.

How Does L-Tyrosine Work?

L-tyrosine is thought to increase levels of dopamine and norepinephrine by providing the building blocks needed to make these neurotransmitters. The chemical pathway is as follows: L-tyrosine is converted to L-dopa by the enzyme tyrosine hydroxylase, and L-dopa is the direct precursor to dopamine. Further, dopamine is converted into norepinephrine.

By providing more of the building blocks for dopamine and norepinephrine, L-tyrosine is thought to potentially improve symptoms of ADHD and executive function overall.

Is L-Tyrosine the Same as Adderall?

L-tyrosine is sometime thought of as "over-the-counter Adderall", a stimulant medication approved to treat ADHD. Both L-tyrosine and Adderall can potentially increase dopamine in different ways, however only Adderall has a clearly proven efficacy in the treatment of ADHD.

Adderall vs. L-tyrosine

Adderall is a stimulant that increases levels of the neurotransmitters dopamine and norepinephrine in the brain. In contrast, L-tyrosine is thought to increase levels of dopamine and norepinephrine by providing the building blocks needed to make these neurotransmitters.

What Are the Benefits of L-Tyrosine?

As a dietary supplement, L-tyrosine has been purported to be of use for the following:

  • Improving mental clarity and focus
  • Increasing working memory and episodic memory
  • Heightening alertness
  • Increasing fluid intelligence
  • Improving information processing
  • Mitigating the effect of high cognitive load and stress
  • Increasing energy levels
  • Promoting weight loss
  • Improving athletic performance
  • Lowering blood pressure
  • Reducing symptoms of depression

Many of these claims are not clearly supported by research. Let’s take a closer look at some of the science-backed benefits of L-tyrosine.

Cognitive flexibility

L-tyrosine is thought to improve cognitive flexibility. In one study, healthy adults were given either L-tyrosine or a placebo before completing a test that required switching from one task to another.

Those who took L-tyrosine demonstrated more cognitive flexibility than those who took the placebo.

Working memory

Studies have looked at the impact of tyrosine on working memory.

One study found that daily intake of tyrosine through food intake enhances working memory and fluid intelligence in younger and older adults. In a randomized-controlled trial, taking a dose of L-tyrosine improved task performance in people during a test of behavioral inhibition and working memory. Their results also showed the response to tyrosine was moderated by genetic difference in the dopamine D2 receptor. However, this wasn't tested specifically in people with ADHD..

Reducing Stress

Stressful conditions are known to negatively affect cognitive and physical performance. A systematic review of 15 studies showed that a single dose of L-tyrosine mitigated the impact of stress on cognitive tasks. For example, healthy adults who received a dose of tyrosine before being exposed to cold temperatures (a known stressor that can impede performance), did better on cognitive tasks than controls who did not take the tyrosine.

Another study described that L-tyrosine prevents some of the cognitive decline in response to physical stress.

How to Take L-Tyrosine

You can find L-tyrosine supplements at most health food stores. The usual dose is 500 to 2000mg per day. If you choose to try L-tyrosine, it's generally thought best to start with a lower dose and increase it gradually.

You should also talk to your doctor before taking L-tyrosine or any other supplement, especially if you have a health condition or are taking other medications.

How Long Does It Take For L-Tyrosine To Work

The effects of L-tyrosine may not be immediate and it may take several weeks for you to notice any changes. If you don’t notice any improvement after a few weeks, you may want to try a higher dose or talk to your doctor about other treatment options.

Possible Side Effects

L-tyrosine is generally considered safe when taken in recommended doses. However, it can cause some side effects, such as the following:

  • Anxiety
  • Headache
  • High blood pressure
  • Insomnia
  • Nausea
  • Restlessness
  • Skin flushing
  • Stomach upset
  • Vomiting

If you have ADHD, you may be more sensitive to the side effects of L-tyrosine. Therefore, it’s important to start with a lower dose and increase gradually as needed. If you experience any side effects, stop taking the supplement and talk to your doctor.

Who Should Not Take L-Tyrosine?

L-tyrosine is generally considered safe when taken at recommended doses. However, it can cause side effects and can also interact with some medications. If you have an underlying health condition or are taking medications, it is especially important to speak to your doctor before taking L-tyrosine or any other supplement.

Takeaways

Although there is some evidence that L-tyrosine may help with certain aspects of cognitive performance, there is limited evidence to support it as an effective treatment for attention deficit hyperactivity disorder (ADHD) symptoms.

However, more research is needed. If you’re considering taking L-tyrosine for ADHD, talk to your doctor first. They can help you weigh the potential risks and benefits and determine if L-tyrosine is right for you.

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Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Arlin Cuncic

By Arlin Cuncic, MA
Arlin Cuncic, MA, is the author of The Anxiety Workbook and founder of the website About Social Anxiety. She has a Master's degree in clinical psychology.