Our evidence-based analysis of L-Tyrosine features unique references to scientific papers and anecdotal reports.

What Is L-Tyrosine?

L-Tyrosine naturally-occurring amino acid that is essential to both physical and mental functions. It is the precursor for dopamine, adrenaline, and norepinephrine, three of the most important neurotransmitters.

Dopamine is associated with reward and pleasure and plays an important role in mood, motivation, and cognition; adrenaline and norepinephrine are the hormones behind the body’s “fight or flight” response to stress, and together they influence energy by modulating heart rate, blood pressure, and blood sugar levels. These three neurotransmitters, which share a distinct chemical structure, are called catecholamines.‍[1]

L-Tyrosine is also necessary to the production of both thyroid hormones, which regulate metabolism, and melanin, a natural pigment occurring in the hair, skin, and eyes.

L-Tyrosine is available in high-protein dietary sources like dairy products, meats, fish, and eggs, but the body also produces it from another amino acid called L-phenylalanine. Because the body can produce adequate amounts of L-tyrosine, supplementation isn’t essential for basic health.

Research suggests that supplemental L-tyrosine can enhance cognition, increase energy, boost mood, and increase motivation, particularly for people under physical or environmental stress.

Benefits and Effects of L-Tyrosine

L-Tyrosine has been proven to offer various benefits for both mind and body, particularly in situations that involve a degree of physical or mental stress.

Cognitive Enhancement Under Stress

Decades of studies show that supplemental L-tyrosine can significantly boost cognition in stressful conditions, effectively offsetting deficits in working memory and information processing created by environmental stressors such as extreme weather or intense cognitive demand.

By creating a “buffer” of raw material from which the brain can produce neurotransmitters, L-tyrosine supplementation may prevent the depletion associated with stress.‍[2]

L-Tyrosine has also been shown to improve cognitive performance by modulating the body’s physical response to stress. In a 1999 military study of cadets on a combat training course, subjects taking L-tyrosine supplementation had significantly lower systolic blood pressure than those receiving placebo, and performed better on memory and tracking tasks.‍[3]

L-Tyrosine was even shown to offset the effects of sleep deprivation, an environmental stressor that typically degrades the performance of cognitive tasks. In a 1995 study, sleep-deprived individuals receiving supplemental L-tyrosine performed significantly better at various cognitive and psychomotor tasks than a similar group that was given a placebo.‍[4]

Improved Working Memory

L-Tyrosine appears to boost working memory as tasks become increasingly more challenging. A 2013 study on adults doing a progressively challenging mental task found that participants who took supplemental tyrosine did better on the task’s more difficult levels but showed little or no improvement on the easier levels.‍[5]

The researchers concluded that L-tyrosine selectively targets cognitive control operations, providing more resources under mentally demanding tasks.

Increased Cognitive Flexibility

A small 2015 study involving 22 healthy adults showed that supplemental L-tyrosine enhanced cognitive flexibility, the ability to switch between tasks or modalities of thought.‍[6] This result was attributed mostly to the fact that L-tyrosine increases brain levels of dopamine, which is believed to control cognitive flexibility.

ADHD Treatment and Focus Enhancement

Low levels of tyrosine are not uncommon among people diagnosed with ADHD, and supplemental L-tyrosine has been studied for its potential as an adjunct treatment for the disorder. A 2011 trial involving both adult and pediatric ADHD patients showed that 77% of patients treated with L-tyrosine alone showed significant improvement over a period of 10 weeks.‍[7]

Further studies indicated that pharmaceutical ADHD medication’s positive effects were significantly enhanced by taking L-tyrosine alongside it.‍[8]

Anecdotal reports from users claim similar experiences saying that it provides energy, focus, and motivation similar to the effects of Adderall.‍[9]‍[10]

How It Works

L-Tyrosine’s primary mechanisms of action have been extensively studied and are well understood.

Most of its actions are related to its use in the production of catecholamine neurotransmitters dopamine, adrenaline, and norepinephrine; it doesn’t cause them to be produced, but it does provide the raw material from which they’re made.

L-Tyrosine is created when its precursor amino acid, phenylalanine, is metabolized in the liver. Having sufficient levels of L-tyrosine provides a buffer of material the body can use when it needs to produce more catecholamines.

Intense physical or mental stress increases the release of adrenaline, norepinephrine, and dopamine, and levels can quickly become depleted. When this happens, the brain initiates the process of creating more by releasing an enzyme that converts L-tyrosine first into the catecholamine precursor L-DOPA and then into dopamine, part of which is oxidized and converted into norepinephrine and adrenaline.‍[11]

This built-in regulatory system can be seen as an argument in favor of L-tyrosine supplementation. Maintaining sufficient levels of L-tyrosine may increase catecholamine synthesis and release by ensuring enough tyrosine during prolonged periods of stimulation.‍[12]


To increase mental performance or mitigate the effects of stress, a single daily dose of 500–2000 mg of L-tyrosine has been shown to be safe and effective.

Tyrosine supplements are also available as N-Acetyl-L-Tyrosine or NALT, a modified form of L-tyrosine with an acetyl group attached to the tyrosine molecule to enhance bioavailability. NALT is more soluble than the standard form but has a lower conversion rate in the body, so larger doses may be required. Both forms of the supplement provide the same functions and benefits.‍[13]


N-Acetyl-L-Tyrosine Stack for Universal Cognitive Enhancement

For a preformulated nootropic that contains a blend of 11 cognitive enhancing supplements, including NALT, designed to optimize a wide array of cognitive functions, we recommend Mind Lab Pro.

Mind Lab Pro’s strategy aims at all aspects of memory, mental performance, mood and stress resistance, and brain repair, and maintenance. Their combination of nootropics is designed to affect brain energy, neurotransmitters, brain blood flow, brain waves, neuroprotection, and regeneration.

Read our Mind Lab Pro review for a detailed overview.

Side Effects

L-Tyrosine is considered safe when taken at recommended doses.

Commonly reported side effects tend to be mild and temporary, and include headaches, migraine, indigestion, stomach trouble, and gastrointestinal upset.

Contraindications: L-Tyrosine should not be taken by people taking high blood pressure medication, Levodopa, thyroid medication, MAO inhibitors, or stimulants. L-tyrosine should not be taken by individuals with thyroid disease, Graves’ disease, or melanoma. L-Tyrosine has not been proven safe for women who are pregnant or nursing.‍[14]

Where to Buy

L-Tyrosine is readily available in retail stores that sell supplements as well as via online vendors.

We recommend buying L-tyrosine from PureNootropics.net, a one-stop shop for cognitive enhancing supplements.

If you prefer to do your shopping on Amazon.com, we recommend Source Naturals N-Acetyl L-Tyrosine Capsules as a high-quality source of L-tyrosine.

Alternatively, if you’d like to take a supplement that contains a blend of 11 cognitive enhancing nootropics, including NALT, we recommend Mind Lab Pro. Read our Mind Lab Pro review for a detailed overview.

Closing Thoughts

L-Tyrosine is a tested and proven supplement with evidence that it can enhance memory, increase cognitive flexibility, and improve mental performance in individuals exposed to acute stress or elevated cognitive demand.

One of the most interesting aspects of L-tyrosine supplementation is that it performs best under pressure, but that doesn’t necessarily mean that L-tyrosine’s effectiveness is limited to extreme situations. While there is limited research on this aspect of L-tyrosine, the few studies that have been done, combined with anecdotal evidence from users, indicate that L-tyrosine may well be beneficial even for those not experiencing military-grade stress.

Working or studying long hours, struggling with anxiety, and even intense exercise are all stressors that can have a negative effect on cognition, and L-tyrosine supplementation may help.

Planning to start a new supplementation regimen? See our medical disclaimer.

This page was last updated on July 16, 2021.