Written by Tara Boustany on
September 5, 2021
Reading Time: 7 minutes

Medically Reviewed by our Medical Affairs Team

Written by Tara Boustany on:

Do you suffer from ADHD? Have you ever wondered if there is a supplement that can help with your symptoms? If so, this article is for you.

L-tyrosine is a non-essential amino acid, meaning that you don’t have to get it from food. It is naturally produced in the body by another amino acid called phenylalanine.

Also, l-tyrosine can be found in dairy products, meats, fish, eggs, nuts, beans, oats, and wheat. It is used to make proteins and other important compounds in the body too. 

This article will cover everything from L-tyrosine uses to its dosages and potential side effects. The article will also tackle the supplement use in ADHD. Effectively, L-tyrosine helps with inattention, the first type of ADHD, by increasing functions such as memory and focus.

Read this article to find out more about L-tyrosine and its role in ADHD.

Everything You Need to Know About L-Tyrosine

Potential Uses

L-Tyrosine is present in protein-rich foods, including peanuts, fish, chicken, turkey, soy, and cheese. It is also present in pumpkin seeds, sesame seeds, avocado, and bananas.

Treatment of Phenylketonuria (PKU)

PKU is a genetic condition where people are not able to process the amino acid phenylalanine. Phenylalanine is the amino acid that produces L-tyrosine.

Thus, people with PKU may have elevated levels of phenylalanine and low levels of L-tyrosine in their bodies. Treatment of PKU includes restricting dietary sources of phenylalanine and taking L-tyrosine supplements.

However, the evidence on PKU treatment is mixed. In one review, 56 people with PKU were given L-tyrosine with or instead of a phenylalanine-restricted diet.

Researchers investigated the effect of L-tyrosine supplementation on many factors. They include intelligence, growth, nutritional status, mortality rates, and quality of life.

They found no significant differences between L-tyrosine supplements and a placebo. The researchers concluded that no recommendations can be made on L-tyrosine as a PKU treatment. Also, they concluded that more studies are required to provide further evidence.

Treatment of Depression

L-Tyrosine has been suggested to help in the treatment of depression. Depression happens when your brain chemicals become unbalanced. It is usually treated by taking antidepressants. Because L-tyrosine can increase the production of important brain chemicals, it may act as an antidepressant.

However, there is not enough evidence to support this claim. In one study, 65 patients with depression were either given 100 mg/kg/day L-tyrosine, 2.5 mg/kg/day of an antidepressant, or a placebo for 4 weeks. There was no evidence that L-tyrosine supplementation had any antidepressant activity.

Yet, in another study, 12 patients with dopamine-dependent depression received treatment with L-tyrosine. Dopamine-dependent depression is characterized by a lack of energy and motivation. Mood and sleep showed an immediate improvement early in the treatment.

Thus, L-tyrosine was beneficial in relieving symptoms of depression. But, this treatment is not effective in other types of depression. All in all, evidence regarding L-tyrosine use as treatment of depression is mixed. More studies are needed to evaluate its potential benefits in the treatment of depression.

Dosing

Studies use dosages ranging from 100 to 150 mg/kg per day. Manufacturers frequently recommend 500 to 1,500 mg/day, and dosages of more than 12 g/day are not recommended. When combined with vitamin B6, folate, and copper, the benefits of L-tyrosine may be enhanced.

Side Effects 

According to the Food and Drug Administration, L-tyrosine is “generally recognized as safe” (GRAS). However, L-tyrosine supplements may trigger a chronic migraine. Information on other side effects is limited. 

When to Avoid Taking L-tyrosine

While L-tyrosine is relatively safe for most people, it can interact with medications. Consult your doctor before starting supplementation with L-tyrosine in the following cases: 

Graves disease or hyperthyroidism

Graves’ disease is a disorder that results in the overproduction of chemicals called the thyroid hormones. Hyperthyroidism, or overactive thyroid, also occurs due to excessive thyroid hormone production.

L-tyrosine may increase levels of thyroid hormone too. Thus, if you suffer from Graves disease or hyperthyroidism, you should be cautious when taking this supplement.

Monoamine oxidase inhibitors (MAOIs)

MAOIs include:

MAOIs are old antidepressants that work ​​by blocking the enzyme responsible for the breakdown of excess tyramine in the body. Tyramine is an amino acid that helps control blood pressure and is formed through L-tyrosine degradation.

In foods, L-tyrosine and phenylalanine are converted to tyramine by an enzyme in microorganisms. This results in the build-up of Tyramine. Foods containing considerable amounts of tyramine include meats that are potentially aged.

Smoked, marinated, and fermented foods, such as cheeses and alcoholic beverages, are also rich in tyramine. Tyramine-rich foods can react with MAOIs and cause increased blood pressure to a dangerous level. This is the “cheese effect”.

Yet, it is unknown if the supplement leads to a buildup of tyramine in the body. For those taking MAOIs, caution is advised.

Levodopa

Levodopa, also known as L-dopa, is a medication used to treat Parkinson’s disease. L-dopa and L-tyrosine compete for absorption in the small intestine. L-Tyrosine might decrease how much levodopa the body absorbs. To avoid this interaction, these two medicines should be taken several hours apart.

What is ADHD? 

Attention deficit hyperactivity disorder, or ADHD, is one of the most common disorders of childhood. It is usually first diagnosed in childhood and often lasts into adulthood.

ADHD is characterized by inattention, impulsivity, and/or hyperactivity. It affects about 10% of school children worldwide with symptoms continuing into adulthood in about 60% of cases. ADHD is mainly treated with a combination of behavior therapy and medication.

Despite the efficacy of ADHD medications, new evidence shows that supplements may be a promising therapy. Adjunctive therapy includes vitamins, minerals, herbs, and hormones. But, because these supplements are not regulated by the FDA, it means that there are no established safety and use protocols.

Thus, ADHD supplements might be helpful but they need careful consideration with a doctor first.

L-Tyrosine and ADHD in Children

Prior research showed that lower L-tyrosine levels in the body might be linked to ADHD symptoms in youngsters. However, a study published in 2016 found that most children with ADHD have normal levels of amino acid in their blood.

According to a 2011 study, children with ADHD responded favorably to a combination of L-tyrosine and 5-HTP, another amino acid. However, these findings were later retracted.

L-Tyrosine and ADHD in Adults

The most important evidence for the use of L-tyrosine to treat ADHD symptoms in adults comes from a small 1987 study.

During the study, 12 patients with ADHD reported a reduction in symptoms after taking the supplement for the first 2 weeks. But, by six weeks, individuals developed a tolerance. By week 8, the initial L-tyrosine effects began to diminish. The researchers concluded that L-tyrosine was ineffective in treating adult ADHD.

L-Tyrosine and ADHD Medications

There are no known drug interactions between L-tyrosine and common ADHD medications. Examples of ADHD medications include Ritalin or Adderall. But, that doesn’t mean the supplement is risk-free.

As we mentioned earlier, supplements aren’t controlled by the Food and Drug Administration in the same way as prescription drugs. This means there is no guarantee that what’s on the bottle is actually in the bottle.

Thus, before you consider mixing L-tyrosine with ADHD medications, consult with your doctor. They will guide you and warn you about any potential side effects and interactions.

A Small Conclusion on L-tyrosine Use in ADHD

More research needs to be done because the existing studies work with only a few people. Also, there is limited research on ADHD and L-tyrosine, and some data has been proven not effective or been retracted.

Because there are different types of ADHD, and everyone responds to medication differently. Always consult a health care provider before starting L-tyrosine. They will help you determine the best approach to symptom management.

Other ADHD Supplements 

Vitamins

Vitamins are crucial for normal brain development and have been suggested as a treatment for ADHD. A lot of studies show positive results for the use of Vitamins B, C, and D in ADHD.

Yet, further research is necessary to determine whether B vitamins supplementation may play a role in the treatment of ADHD.

Omega-3 Polyunsaturated Fatty Acids

The omega-3 fatty acid is an important brain nutrient. There are two types of omega-3 fatty acids in foods — eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). DHA can be found in fatty fish, fish oil pills, and krill oil. Omega-3 fatty acids may also be found in plants and are called alpha-linolenic (ALA).

Studies have shown that people with ADHD have lower levels of DHA in their blood than those who don’t have this condition.  But, the current evidence is inconclusive on whether omega-3 fatty acids could provide any benefit in ADHD.

Iron

According to a 2018 review, children with iron deficiency were more likely to have ADHD. Also, iron deficiency was linked to more severe ADHD symptoms in these children. Thus, iron supplementation may help iron-deficient children with ADHD. However, further research is needed.

Zinc

Foods high in zinc include seafood, red meat, poultry, dairy products, beans, nuts, whole grains, and fortified cereals. Zinc deficiencies are one possible cause of ADHD in children.

According to a 2015 review, zinc supplementation may help relieve ADHD symptoms in children with zinc deficiency. However, it is not clear whether zinc supplements help children who do not have a zinc deficiency.

Magnesium

Foods rich in magnesium include dairy products, whole grains, beans, and leafy greens. A 2020 study concluded that Vitamin D and magnesium improved conduct and social problems in children with ADHD. It also helped with anxiety and shyness.

In another study, 40 children with ADHD received vitamin B6 and magnesium supplements. Hyperactivity, aggressiveness, and mental focus improved in all children after 8 weeks. A few weeks after supplements were stopped, the ADHD symptoms returned.

Ginkgo Biloba

Ginkgo biloba is an herb that derives from the leaves of the G. Biloba tree. Ginkgo biloba may also be a useful natural treatment for ADHD.

However, larger studies are needed to evaluate the potential benefits of ginkgo biloba for ADHD. The plant might also increase the risk of bleeding. Thus, people who are on blood-thinning medications or have bleeding problems should be careful.

In 2013, a small study looked at the effects of ginkgo biloba on childhood ADHD. After administration of the herb, children showed improvements in attention, hyperactivity, and impulsiveness.

In a 2014 review, ginkgo biloba was found to be much less effective than traditional ADHD medications. However, it is unclear whether the herb is any better than a placebo. The review stated that due to the risk of increased bleeding with ginkgo biloba, it should not be used for ADHD.

More Supplements for ADHD

The list of supplements that may be used as a potential treatment for ADHD does not stop here. A lot of other supplements are being studied as well and include:

  • Brahmi supplements
  • Gotu Kola supplements
  • Korea red ginseng supplements
  • Valerian root and lemon balm supplements
  • Pycnogenol supplements
  • St. John’s wort supplements
  • Melatonin supplements

Yet, all of the studies are still in their early stages, and extra research needs to be done before jumping to any conclusion.

The Bottom Line

L-tyrosine is a popular dietary supplement that is consumed for a variety of purposes. There is strong evidence that this supplement improves mental performance. Supplementing with it is safe, even in high doses, but it may interact with some drugs, necessitating caution.

While L-tyrosine appears to have many health benefits, their significance remains unproven. In the absence of extra research, L-tyrosine and other supplements should only be used under your doctor’s supervision. Also, make sure your doctor knows about all your medical conditions and medications.

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