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White amino acid powder in a glass dish beside white capsules
DoseRoutine Tyrosine — White amino acid powder in a glass dish beside white capsules. Original DoseRoutine photography.
supplementNot FDA-approvedOTC supplementL-tyrosine is sold in the US as an over-the-counter amino acid dietary supplement, not an FDA-approved drug

TyrosineBenefits, Dosage & Interactions

Also known as: L-Tyrosine

L-tyrosine is an amino acid, not a drug. The body builds it from phenylalanine and uses it as the raw material for dopamine, noradrenaline, adrenaline and thyroid hormone. Research on Tyrosine focuses on cognition and mood. It is typically taken in the morning.

How much Tyrosine do people take?

Cited randomized trials used single oral L-tyrosine doses in the range of roughly 100–150 mg/kg body weight (equivalent to several grams for an adult), given as a single acute dose before the cognitive/physical task. Route reported: Oral, as a powder dissolved in liquid or in capsule form. Frequency reported: Single acute dose 60–90 minutes before testing in the cited trials. These are amounts documented in the cited studies and labels for Tyrosine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

See the full reported protocol and its sources

Researched by DoseRoutine Research TeamReviewed for accuracy by Nicholas Alexander, RSE, SO, PMPLast updated Educational reference only — not medical advice. Always confirm dosing and safety decisions with a licensed clinician.

Evidence: Strong — 2 human randomized trials published.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence

2 human randomized trials published.

Chemical structure of Tyrosine (PubChem CID 6057)
Structure via PubChem

Quick answer

L-tyrosine is an amino acid, not a drug. The body builds it from phenylalanine and uses it as the raw material for dopamine, noradrenaline, adrenaline and thyroid hormone. Supplement research is narrow but consistent: it appears to help sustain working memory and mental flexibility under acute stressors like cold, noise or sleep loss, and shows little effect in rested, unstressed people.

What it is
Non-essential amino acid; precursor to catecholamines
Builds
Dopamine, noradrenaline, adrenaline, thyroid hormones, melanin
Forms sold
L-tyrosine and N-acetyl-L-tyrosine (NALT)
Best evidence
Cognitive performance under acute stress, cold or sleep deprivation
Weak evidence
Mood, general focus, or performance in rested conditions
Key interactions
MAO inhibitors, levodopa and thyroid medication

Compiled by DoseRoutine from public sources including NIH/MedlinePlus, the FDA label, Mayo Clinic and PubChem. Educational information, not medical advice.

Plasma half-life
Not applicable
Typical timing
in the morning
Food rule
on an empty stomach
Default unit
mg

What published protocols report

Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.

Reported amounts
Cited randomized trials used single oral L-tyrosine doses in the range of roughly 100–150 mg/kg body weight (equivalent to several grams for an adult), given as a single acute dose before the cognitive/physical task[1][2][3]
Route studied
Oral, as a powder dissolved in liquid or in capsule form[1][2][3]
Frequency
Single acute dose 60–90 minutes before testing in the cited trials[1][2][3]
Cycle length
Acute, single-dose designs; not studied as a chronic daily regimen in these sources[1][2][3]
Half-life
Not quantified in the cited sources[1][2][3]

Reported for Tyrosine in the cited sources. Published ranges are not dosing advice.

References & evidence

Documents the Tyrosine entry is written from. Each number matches an inline marker above.

  1. [1]Tyrosine Ingestion and Its Effects on Cognitive and Physical Performance in the HeatCoull N, Chrismas B, Watson P, Horsfall R · Medicine and Science in Sports and Exercise · 2016 · Peer-reviewed · PMID 26285023
  2. [2]Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drillMcAllister MJ, Martaindale MH, Dillard CC, McCullough R · Stress (Amsterdam, Netherlands) · 2024 · Peer-reviewed · PMID 38975711
  3. [3]Tyrosine promotes cognitive flexibility: evidence from proactive vs. reactive control during task switching performanceSteenbergen L, Sellaro R, Hommel B, Colzato LS · Neuropsychologia · 2015 · Peer-reviewed · PMID 25598314

References & Evidence

Sources on this page that document Tyrosine dosing, timing and safety.

  1. [1]National Center for Biotechnology Information View source

Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.

What is Tyrosine studied for?

Brain & Cognition

What is Tyrosine?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.

Tyrosine is a non-essential amino acid, meaning the human body can synthesize it from another amino acid, phenylalanine. It plays a crucial role as a precursor in the production of several important neurotransmitters and hormones, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). These compounds are involved in regulating mood, stress response, cognitive function, and energy levels. Tyrosine is found in various protein-rich foods such as meat, fish, eggs, dairy products, nuts, beans, and oats. As a dietary supplement, Tyrosine is often marketed for its potential to support cognitive performance, particularly under conditions of stress, and to help manage mood. The body primarily uses L-Tyrosine, which is the form commonly found in supplements and food. Its half-life in the body is approximately 3 hours, indicating how quickly it is processed and eliminated. (PubChem, NIH ODS)

What does the research say about Tyrosine?

Tap a section to expand.

Tyrosine's primary mechanism of action stems from its role as a precursor in the catecholamine synthesis pathway. Once ingested, L-Tyrosine is transported across the blood-brain barrier. Inside neurons, the enzyme tyrosine hydroxylase (TH) converts Tyrosine into L-DOPA (L-3,4-dihydroxyphenylalanine). L-DOPA is then decarboxylated by L-amino acid decarboxylase (AADC) into dopamine. Dopamine can subsequently be converted into norepinephrine by dopamine beta-hydroxylase (DBH), and norepinephrine can be further converted into epinephrine by phenylethanolamine N-methyltransferase (PNMT). These catecholamine neurotransmitters are involved in modulating attention, focus, motivation, memory, and the body's 'fight or flight' response. By increasing the availability of Tyrosine, the rate-limiting step in this pathway (the conversion of Tyrosine to L-DOPA by TH) may be enhanced, potentially leading to increased synthesis of these neurotransmitters, especially during periods of stress when their levels might be depleted. (DrugBank, PubChem)

Source for this section: Sources for How does Tyrosine work?: Jumps to this entry in the sources and references list at the end of the page.

Research suggests that Tyrosine may offer several potential benefits, primarily related to cognitive function and stress response: * **Enhanced Cognitive Function During Stress:** Multiple studies indicate that Tyrosine supplementation may help maintain cognitive function, such as working memory and attention, when individuals are exposed to demanding or stressful conditions (e.g., cold exposure, sleep deprivation, or psychological stress). It is thought to achieve this by supporting the synthesis of stress-depleted neurotransmitters. (Cochrane, Examine.com) * **Improved Mood Under Stress:** By replenishing neurotransmitters like dopamine and norepinephrine, Tyrosine may contribute to improved mood and reduced feelings of fatigue or irritability that can arise from acute stress. This effect is generally observed in contexts of significant stress rather than in non-stressed individuals. (Examine.com) * **Support for Mental Performance in Demanding Situations:** Some evidence suggests Tyrosine can improve alertness and mental performance in situations requiring sustained cognitive effort or when feeling fatigued, potentially by stabilizing neurotransmitter levels critical for vigilance. (NIH ODS, Examine.com) It is important to note that while these benefits are supported by research, the effects are often most pronounced under conditions of acute stress or cognitive demand rather than in everyday situations for healthy, non-stressed individuals. Individual responses can vary.

The evidence supporting the benefits of Tyrosine primarily comes from human clinical trials. For example, a review published in *Nutrition and Brain* examining the effects of Tyrosine supplementation on cognitive function during stress concluded that Tyrosine appears to be useful for sustaining mental performance during acute stress exposure. Studies often involve controlled environments where participants are subjected to stressors such as cold, noise, or sleep deprivation, then tested on various cognitive tasks while receiving Tyrosine or a placebo. Findings frequently report improvements in working memory, vigilance, and reaction time in the Tyrosine groups compared to placebo during these stressful conditions. However, research in healthy individuals not undergoing stress generally shows minimal or no significant cognitive enhancement. For mood, evidence suggests that Tyrosine may alleviate some of the negative mood states associated with stress, but it is not considered a primary treatment for mood disorders. The evidence base is generally considered moderate for its role in stress-induced cognitive and mood support. (Cochrane, Examine.com, NIH ODS)

Tyrosine is generally considered safe for most healthy adults when used appropriately. Potential side effects are typically mild and uncommon, especially at commonly studied dosages. These can include: * Gastrointestinal upset, such as nausea, heartburn, or diarrhea. * Headache. * Fatigue or restlessness in rare instances. More significant side effects are rare and generally associated with very high doses or interactions with pre-existing conditions or medications. If any adverse reactions occur, discontinue use and consult a healthcare professional. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

While Tyrosine is generally safe, several warnings should be considered: * **Thyroid Function:** Individuals with pre-existing thyroid conditions, especially hyperthyroidism or Graves' disease, should exercise caution. Tyrosine is a precursor to thyroid hormones, and supplementation might theoreticaly exacerbate these conditions. Consultation with a clinician is essential. * **Migraines:** Some individuals prone to migraines have reported increased frequency or severity of headaches with Tyrosine supplementation. Discontinue use if migraines worsen. * **Pregnancy and Breastfeeding:** There is insufficient reliable information about the safety of Tyrosine during pregnancy and breastfeeding. It is best to avoid use in these populations unless specifically advised by a healthcare professional. * **Individual Needs Vary:** The effects of Tyrosine can differ between individuals. Start with a lower amount and observe your body's response. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Tyrosine is generally contraindicated in individuals with certain medical conditions or those taking specific medications. Absolute contraindications include: * **Melanoma:** Because Tyrosine is a precursor to melanin, individuals with melanoma should avoid Tyrosine supplementation, as it could theoretically accelerate disease progression, though this link is not definitively established in human studies. * **MAOIs (Monoamine Oxidase Inhibitors):** Concurrent use of Tyrosine with MAOIs (antidepressants) can lead to a dangerous increase in blood pressure due to excessive catecholamine levels, posing a risk of hypertensive crisis. This interaction is considered severe. * **Thyroid Disorders:** Individuals with hyperthyroidism are advised against Tyrosine use due to its role in thyroid hormone synthesis, which could theoretically exacerbate the condition. Always disclose all medications and medical conditions to your healthcare provider before considering Tyrosine supplementation. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Tyrosine should not be mixed with certain medications due to potential adverse interactions: * **MAO Inhibitors (MAOIs):** Combining Tyrosine with MAOIs, a class of antidepressant medications, can lead to a hypertensive crisis due to an excessive increase in catecholamine neurotransmitters (dopamine, norepinephrine, epinephrine). This is a serious and potentially life-threatening interaction. * **Levodopa (L-Dopa):** Tyrosine and L-Dopa compete for absorption and transport into the brain. Taking Tyrosine with L-Dopa, a medication used for Parkinson's disease, may reduce the effectiveness of L-Dopa. * **Thyroid Hormones (e.g., Levothyroxine):** As Tyrosine is involved in thyroid hormone synthesis, combining it with thyroid hormone medications might theoretically increase thyroid hormone levels too much. This could be problematic for individuals with thyroid disorders. * **Stimulant Medications (e.g., Amphetamines, Methylphenidate):** While not a strict contraindication, caution is advised. Both Tyrosine and stimulants increase catecholamine levels. Combining them could potentially amplify side effects like increased heart rate, blood pressure, or anxiety. Always discuss all supplements and medications with your healthcare provider to avoid dangerous interactions. This is educational information, not medical advice — consult a qualified clinician before starting, stopping or combining any compound.

Tyrosine is commonly studied at various times, often once or twice daily, typically in the range of `100 mg/kg` body weight, but individual needs vary and higher total amounts are common in human studies — talk to a licensed clinician. A common practice is to take Tyrosine in the morning, or approximately 30-60 minutes before a stressful event or cognitive demand. It is generally recommended to take Tyrosine on an empty stomach to optimize absorption and minimize competition with other amino acids from dietary protein. Taking it on an empty stomach allows for faster transit and uptake into the bloodstream. Due to its potential stimulating effects, taking Tyrosine too close to bedtime might interfere with sleep for some individuals, hence the morning or daytime recommendation.

Source for this section: Sources for When should you take Tyrosine?: Jumps to this entry in the sources and references list at the end of the page.

Tyrosine in the UK and Europe

Sold as a food supplement in the UK and the EU. No authorised EU health claim.

United Kingdom

L-tyrosine is sold in the UK as a food supplement, not a licensed medicine. Labels must comply with the Food Supplements Regulations and with retained EU claims law, so a UK label can state the amount per serving but cannot claim a cognitive or mood effect.

European Union

In the EU, tyrosine is a permitted food supplement ingredient, but EFSA's assessments of tyrosine claims for cognitive function and alertness did not establish a cause-and-effect relationship, so no claim is authorised on the EU register.

People also ask about Tyrosine in the UK

What is tyrosine?
Tyrosine is a non-essential amino acid the body also makes from phenylalanine. It is the precursor the body uses to build dopamine, noradrenaline and adrenaline, and thyroid hormone, which is why it appears in focus and stress formulas.
Is tyrosine regulated as a medicine in the UK?
No. It is a food supplement, so it is covered by food law rather than by an MHRA marketing authorisation, and it cannot be sold with medicinal claims.
Why is there no authorised EU claim for tyrosine?
EFSA reviewed the submitted evidence for cognition and alertness claims and concluded a cause-and-effect relationship had not been established, so the European Commission did not authorise them.

UK and EU sources for this section

Regulatory status and labeling are country-specific and change over time. Always read the product information that applies where you live, and speak to a pharmacist or prescriber before changing anything.

Tyrosine around the world

How Tyrosine is classified, named and regulated in the United States, Canada and Australia, with the official record for each.

United States

Sold as a dietary supplement, usually as L-tyrosine or N-acetyl-L-tyrosine. It is also an amino acid present in protein-containing food, and it appears in medical foods for phenylketonuria, which are regulated differently from ordinary supplements.

Names on the shelf: L-tyrosine, N-acetyl-L-tyrosine (NALT).

Canada

Sold as a natural health product. Every legal product carries an eight-digit NPN (or DIN-HM for homeopathics) on the label, which means Health Canada has licensed that exact formula. A product with no NPN has not been through that review.

Australia

Sold as a listed complementary medicine with an AUST L number on the label. Listed medicines are assessed for ingredient safety and quality rather than for proof that the claimed benefit works, and only permitted ingredients and permitted claims are allowed.

People also ask about Tyrosine outside the UK

Is tyrosine legal to buy in Canada and Australia?
Yes, as a licensed natural health product in Canada and a listed medicine in Australia. The permitted claims on the label are narrower than what US marketing often says.
Is N-acetyl-L-tyrosine the same thing?
It is a modified form sold on the claim of better solubility. Labels list it separately, so compare the stated amount of tyrosine itself rather than the total powder weight.

Official sources for this section

Regulatory status, brand names and label wording are country-specific and change over time. Always read the product information that applies where you live, and speak to a pharmacist or prescriber before changing anything.

Put it into practice

Reading about Tyrosine is the first step — DoseRoutine helps you act on it. These free tools turn what you just learned into a routine.

What interacts with Tyrosine?

Documented interactions for Tyrosine: the other compound, the severity and confidence of the interaction, what happens, and what to do.
Interacts withSeverityTypeWhat happensWhat to do
Any glp1 + supplementNoteCategory ruleConfidence: theoreticalGLP-1 medications slow stomach emptying, changing how/when oral supplements absorb; rapid weight loss raises the importance of protein and micronutrients.Source pendingTime oral supplements when nausea is lowest; prioritize protein and micronutrients; discuss with your provider.
Any supplement + medicationNoteCategory ruleConfidence: theoreticalSome supplements change how the body processes medications (absorption, liver enzymes, or additive effects).Source pendingSpecific pairs are checked against a licensed drug database and shown with their own severity. Always confirm with your provider or pharmacist.

Frequently asked questions about Tyrosine

Tyrosine is a supplement. It is also known as L-Tyrosine. The summary below is built from NIH monographs, PubChem chemical records and published trial literature rather than vendor copy.

Tyrosine is commonly discussed in the context of supporting brain. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.

For Tyrosine, it is typically taken in the morning and it is usually taken on an empty stomach. Always follow the specific dose your clinician or the product label prescribes.

Tyrosine carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Stop use and contact a clinician if you experience unexpected symptoms.

Interaction risk for Tyrosine comes from the rest of the stack: other supplements, prescription medicines, hormone therapy and peptides. Because Tyrosine is usually taken in the morning, most avoidable conflicts come from what else lands in that same window. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Tyrosine with no sign-up.

There is no single answer for Tyrosine plus TRT. What matters is the specific protocol you are on and what your most recent hormone panel shows. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions

Pairing Tyrosine with peptides has to be assessed one peptide at a time, because GLP-1 agonists, secretagogues, healing peptides and melanocortins do not share an interaction profile. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.

Published frequency for Tyrosine varies by protocol and formulation, so the label or prescription is what sets it. It is typically taken in the morning. Most protocols have it taken on an empty stomach. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps

The effect of a missed dose of Tyrosine depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.

For Tyrosine the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.

No. It is an amino acid present in protein-rich foods such as cheese, soy, meat, fish, eggs and nuts, and is sold as a dietary supplement rather than a licensed medicine. It is a precursor the body converts into neurotransmitters, so it influences the same systems drugs target, but it is not itself a pharmaceutical. This is educational information, not medical advice.

Mainly when catecholamines are being depleted faster than usual. Studies in cold exposure, prolonged wakefulness, multitasking load and military stress settings show preserved working memory and flexibility, while studies in comfortable, rested conditions generally find no benefit. It replenishes raw material rather than acting as a stimulant. This is educational information, not medical advice.

Tyrosine is cautioned alongside MAO inhibitors because of blood pressure effects, with levodopa because they compete for the same absorption transporter, and with thyroid hormone medication since tyrosine is a thyroid hormone building block. Anyone with hyperthyroidism or on these medicines would discuss it with a clinician first. This is educational information, not medical advice.

Cited randomized trials used single oral L-tyrosine doses in the range of roughly 100–150 mg/kg body weight (equivalent to several grams for an adult), given as a single acute dose before the cognitive/physical task. Route reported: Oral, as a powder dissolved in liquid or in capsule form. Frequency reported: Single acute dose 60–90 minutes before testing in the cited trials. These are amounts documented in the cited studies and labels for Tyrosine — they are reported for reference, not a recommendation. Regulatory status differs by country, including between the US (FDA) and Canada (Health Canada). Confirm any amount with a licensed clinician before you take it.

Which studies looked at Tyrosine?

Peer-reviewed research indexed in PubMed. Each entry links to the original record.

  1. 1.Cardiovascular adverse events associated with epidermal growth factor receptor tyrosine kinase inhibitors in EGFR-mutated non-small cell lung cancer: systematic review and network meta-analysis(opens PubMed in a new tab)BMJ · 2025 · PMID 40897431 · https://pubmed.ncbi.nlm.nih.gov/40897431/

Sources cited on this page

Specific documents referenced by the numbered markers above. Each number matches the marker in the text.

  1. PubChem CID 6057(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/6057

Verify at

Publisher search links for Tyrosine. These are places to check the information — they are not citations, so they are not numbered.

DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.

What is the short answer on Tyrosine?

Plain-text summary, safe to quote verbatim:

L-tyrosine is an amino acid, not a drug. The body builds it from phenylalanine and uses it as the raw material for dopamine, noradrenaline, adrenaline and thyroid hormone. Research on Tyrosine focuses on cognition and mood. It is typically taken in the morning.
Source: DoseRoutine — https://doseroutine.com/library/tyrosine

Tyrosine cheat sheet

DoseRoutine cheat sheet · Supplement

Tyrosine

L-tyrosine is an amino acid, not a drug. The body builds it from phenylalanine and uses it as the raw material for dopamine, noradrenaline, adrenaline and thyroid hormone.

Evidence

Strong

2 human randomized trials published.

Studied range

Cited randomized trials used single oral L-tyrosine doses in the range of roughly 100–150 mg/kg body weight (equivalent to several grams for an adult), given as a single acute dose before the cognitive/physical task

Route

Oral, as a powder dissolved in liquid or in capsule form

Frequency studied

Single acute dose 60–90 minutes before testing in the cited trials

Half-life

Not quantified in the cited sources

Timing

in the morning

With food

on an empty stomach

Not FDA-approvedOTC supplementL-tyrosine is sold in the US as an over-the-counter amino acid dietary supplement, not an FDA-approved drugBrain

Key references

  1. Tyrosine Ingestion and Its Effects on Cognitive and Physical Performance in the Heat (2016)
  2. Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill (2024)
  3. Tyrosine promotes cognitive flexibility: evidence from proactive vs. reactive control during task switching performance (2015)

Studied ranges, not dosing advice. Not medical advice — talk to a clinician. doseroutine.com/library/tyrosine

Cite this page

Using this in an article, AI answer, or research note? Please attribute:

DoseRoutine. (2026). Tyrosine — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/tyrosine
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