NutriStack
InfoSynergy
Vitamin B6
Vitamin B6 (PLP) is a required cofactor for tyrosine hydroxylase, which converts L-tyrosine to L-DOPA in the dopamine synthesis pathway.
Recommendation: Take B6 with L-tyrosine to support efficient dopamine production.
L-Tyrosine
Amino Acid ·Moderate evidence ·Reviewed May 2026
Precursor to dopamine, norepinephrine, and epinephrine. Excellent for maintaining cognitive performance under stress, sleep deprivation, or multi-tasking demands.
The bottom line
Evidence rating moderate. Most-documented uses: focus under stress, dopamine support, cognitive resilience. 17 sources indexed (1989–2026), with 12 interaction records on file.
The science
How it works, mechanistically.
Core mechanism
Hydroxylated by tyrosine hydroxylase (rate-limiting step) to L-DOPA, then converted to dopamine by aromatic L-amino acid decarboxylase. Dopamine is further converted to norepinephrine and epinephrine. Replenishes catecholamine stores depleted by stress.14,1
Class
Non-Essential Amino Acid
Found in food
Cheese, Chicken, Turkey
Low-status signs
Not essential, but low intake may impair stress resilience
Absorption
Best on an empty stomach
Dosing
Dosing & protocol.
Common range
500–2,000 mg daily
Recommended form
L-tyrosine (better absorbed than NALT)
Take on empty stomach 30 min before meals for best brain uptake; competes with other amino acids1,3
Dosing protocol
Maintain · 500-2000 mg, 30-60 min before stress or cognitive demand
Empty stomach absorption is faster. Avoid late evening if it feels activating.
No cycling requiredNo tolerance buildup
Forms
Forms & what to buy.
Ranked by evidence and value.
L-Tyrosine Recommended
Rank 1: standard free amino acid form. Limited direct form-comparison evidence; ranking is based on review or mechanistic data (PMID: 21437603). Take away from protein if targeting acute effects.
N-Acetyl-L-Tyrosine
Rank 2: more soluble derivative. May not raise tyrosine as efficiently as free tyrosine.
L-Tyrosine Capsules
Rank 3: portable form. Capsules may require multiple pills for higher doses.
Cost
What it actually costs.
Real-world pricing across three quality tiers. Assumes L-Tyrosine.
BudgetBest value
$3.00 /mo
$0.10 per dose
Mid
$6.60 /mo
$0.22 per dose
Premium
$13.50 /mo
$0.45 per dose
Assumes 500-2,000 mg/day. Vendor basis: NOW/iHerb, Vitacost, BulkSupplements powder, and Amazon marketplace; NALT blends are not used for the base tier. Updated 2026-05-28.
From food
The same dose, as food.
How much you'd eat to match a supplemental dose.
500-2,000 mg L-tyrosine
About 3-5 ounces cheese, chicken, turkey, fish, beef, soy foods, or almonds can provide gram-level tyrosine.
Whole protein sources are practical tyrosine sources.
Goals
Goal-based dosing.
Lab work
Markers to track.
What to test, the optimal window inside the conventional range, and how long a response takes.
Plasma Tyrosine Tyrosine
L-tyrosine (500 to 2000 mg) raises plasma tyrosine acutely; supports catecholamine synthesis under stress.11,14
Optimal
55–80 micromol/L
Conventional
45–90 micromol/L
Responds in
Peak plasma at 1 to 2 hours; chronic intake shifts steady-state within days.
45optimal90
Hold supplement 12 hours before draw to assess baseline. Tyrosine is also relevant in phenylketonuria screening (high phenylalanine, low tyrosine).
PhenylalanineTSH
Why people use it
Symptoms it's matched to.
Where this appears in the symptom-to-supplement map, ranked by relevance.
Low motivation / apathy
78% relevance
L-tyrosine is the amino acid precursor to dopamine and norepinephrine, catecholamines involved in drive, reward, and goal-directed behavior.10,17
MoodEmerging evidenceL-tyrosine (free-form amino acid)
Most useful under acute stress or sleep deprivation; take on an empty stomach away from protein.
Sleep-deprived cognitive performance
78% relevance
L-tyrosine is a precursor to dopamine and norepinephrine, and supplementation may help sustain working memory and cognitive flexibility under acute stressors like sleep loss.6,12
CognitiveModerate evidenceL-tyrosine powder or capsules, 500 to 2000 mg on an empty stomach
Most studied for short-term, high-demand situations; it supports performance but does not replace recovery sleep.
ADHD-type inattention
62% relevance
L-tyrosine is the amino acid precursor to dopamine and norepinephrine and may support focus under stress or sleep loss, though direct ADHD trials are weak.10,17
CognitiveInsufficient evidenceL-tyrosine powder or capsules, 500 to 2,000 mg on an empty stomach in the morning
ADHD-specific evidence is limited; avoid combining with stimulant medication without clinician guidance.
Nicotine / smoking cessation support
62% relevance
As a dopamine precursor, L-tyrosine may help replenish catecholamines and theoretically ease the low mood and poor focus that follow nicotine withdrawal, but direct cessation evidence is essentially absent.14
NeurologicInsufficient evidenceFree-form L-tyrosine, 500 to 1000 mg on an empty stomach in the morning
Avoid late-day dosing if it disrupts sleep; not a substitute for proven quit medications, which a clinician can prescribe.
Sluggish thyroid / cold intolerance
60% relevance
Tyrosine is the amino acid backbone combined with iodine to form thyroid hormone, though supplementation does not reliably raise output when intake is already adequate.7,1
HormoneInsufficient evidenceL-tyrosine (away from meals)
Direct evidence for treating hypothyroidism is weak, and it should not replace iodine repletion or thyroid medication.
Lightheaded on standing / orthostatic
55% relevance
Tyrosine is a precursor to norepinephrine, which raises vascular tone, so it is theorized to support blood pressure in orthostatic intolerance.1,2
CardiometabolicInsufficient evidenceL-tyrosine, 500 to 1000 mg in the morning on an empty stomach
Human evidence for orthostatic symptoms is very limited; recurrent fainting or marked dizziness needs a clinician to evaluate for POTS or other causes.
Protocols
Featured in protocols.
Evidence-based stacks that include it, with the exact dose and timing each one uses.
Focus & Cognition Protocol
FocusOptionalModerate evidenceIntermediate$40-65/mo
Dose here
500 mg
Timing
Morning, empty stomach
Precursor to dopamine and norepinephrine; particularly effective under stress or sleep deprivation14
Pre-Workout Protocol
Athletic PerformanceOptionalModerate evidenceBeginner$30-50/mo
Dose here
500-2000 mg
Timing
30 to 60 minutes before training, ideally on an empty stomach since other large amino acids compete for uptake
L-Tyrosine is a precursor to dopamine and norepinephrine and may help maintain cognitive performance and focus under acute physical or environmental stress, with most evidence drawn from cognitive rather than strength outcomes.14,1
Thyroid Support Protocol
Hormonal BalanceOptionalEmerging evidenceIntermediate$25-45/mo
Dose here
500-1000 mg
Timing
Once daily in the morning on an empty stomach
L-Tyrosine is the amino acid backbone that, once iodinated within thyroglobulin, forms the thyroid hormones T4 and T3. Dietary protein normally supplies ample tyrosine, so benefit beyond correcting a frank shortfall is largely theoretical and it is treated as optional support rather than a proven thyroid-boosting agent.10,17
Safety
Full safety detail.
Side effects
- Headache
- Nausea
- Heartburn
- Insomnia if taken late
Contraindications
- MAO inhibitors
- Hyperthyroidism
- Melanoma
Interactions
Interaction records.
InfoSynergy
Iron
Iron is a cofactor for tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis.
Recommendation: Ensure adequate iron status when using L-tyrosine for cognitive support. Iron deficiency impairs catecholamine synthesis.
InfoSynergy
Vitamin C
Vitamin C is a cofactor for dopamine beta-hydroxylase, which converts dopamine (from tyrosine) to norepinephrine.
Recommendation: Take vitamin C with L-tyrosine to support the full catecholamine synthesis pathway from dopamine to norepinephrine.
InfoSynergy
Rhodiola Rosea
Rhodiola inhibits MAO and COMT, reducing dopamine/norepinephrine breakdown. L-tyrosine provides the precursor. Together they increase catecholamine availability.
Recommendation: Effective focus and mental energy stack. Take in the morning for sustained cognitive performance.
InfoSynergy
Vitamin C Liposomal
Vitamin C Liposomal is a cofactor for dopamine beta-hydroxylase, which converts dopamine (from tyrosine) to norepinephrine.
Recommendation: Take vitamin C with L-tyrosine to support the full catecholamine synthesis pathway from dopamine to norepinephrine.
InfoSynergy
Iron Bisglycinate
Iron Bisglycinate is a cofactor for tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis.
Recommendation: Ensure adequate iron bisglycinate status when using L-tyrosine for cognitive support. Iron Bisglycinate deficiency impairs catecholamine synthesis.
InfoConflict
L-Tryptophan
Tyrosine and tryptophan compete with each other (and with other large neutral amino acids) for transport across the blood-brain barrier; co-administration blunts the brain entry of each.
Recommendation: Separate by 2 to 3 hours. Tyrosine in morning for catecholamine support; tryptophan or 5-HTP at night for serotonin and sleep.
InfoSynergy
L-Theanine
L-Tyrosine supports catecholamine production for alertness under stress while L-theanine promotes calm focus, so the pair tends to deliver activated attention without as much of the jittery edge of stimulation alone.
Recommendation: Reasonable nootropic stack for focus under stress. A common pairing is L-tyrosine 500mg to 2000mg with L-theanine 100mg to 200mg taken earlier in the day.
ModerateCaution
5-HTP
L-Tyrosine (a catecholamine precursor) and 5-HTP (a serotonin precursor) compete for the same blood-brain-barrier transporter, and unbalanced chronic dosing of one alone can deplete the neurotransmitter pool made from the other.
Recommendation: If using both for mood or sleep, balance the precursors rather than mega-dosing one, and separate intake (for example tyrosine in the morning, 5-HTP in the evening). Avoid this stack entirely if taking SSRIs, SNRIs, or MAOIs.
InfoSynergy
Iodine
Iodine and L-tyrosine are the two raw materials the thyroid combines to build thyroid hormone, so adequacy of both supports normal hormone synthesis.
Recommendation: Can be taken together for thyroid support. Avoid excess iodine, which can paradoxically impair thyroid function, and use cautiously if you have a thyroid disorder.
InfoTiming Sensitive
BCAAs
People take L-tyrosine to support catecholamine production for focus, alertness, and stress resilience. Because tyrosine and BCAAs share the same brain transporter, a simultaneous large BCAA dose can compete with tyrosine for entry into the central nervous system and slightly dampen its cognitive or stress-buffering effect. This is an efficacy-timing issue, not a toxicity concern, and the magnitude is generally smaller than the tryptophan case because tyrosine-to-catecholamine conversion is only rate-limited under high neuronal firing.
Recommendation: If using L-tyrosine for cognitive or stress benefit, take it 1 to 2 hours apart from a large BCAA serving and ideally away from high-protein meals (which contain abundant competing amino acids). Tyrosine on a relatively empty stomach maximizes its brain uptake. Small BCAA amounts are unlikely to matter; the concern is mainly with concentrated BCAA boluses taken in the same window.
ModerateTiming Sensitive
Levodopa/Carbidopa
L-tyrosine is a large neutral amino acid and can theoretically compete with levodopa for intestinal and blood-brain barrier transport when taken in large supplemental doses. A short trial of 1,000 mg/day tyrosine in people with Parkinson's disease receiving dopaminergic therapy was well tolerated, so the concern is mainly high-dose or poorly timed use. Taking tyrosine close to levodopa could still make motor response less predictable in protein-sensitive patients.
Recommendation: Do not take L-tyrosine at the same time as levodopa/carbidopa. Separate high-dose tyrosine from levodopa by at least 2 hours, and stop the supplement if you notice more wearing off, delayed on, nausea, or dyskinesia. Keep your levodopa schedule consistent and tell your prescriber before using tyrosine daily.
Sources
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Meta-analyses & systematic reviews
2- 1The effect of tyrosine supplementation on whole-body endurance performance in physically active population: A systematic review and meta-analysis including GRADE qualificationNeeds reviewPMIDSolon-Júnior LJF, Boullosa Alvarez DA, Martinez Gonzalez B et al. · Journal of sports sciences · 2023
Solon-Júnior LJF, Boullosa Alvarez DA, Martinez Gonzalez B et al.. The effect of tyrosine supplementation on whole-body endurance performance in physically active population: A systematic review and meta-analysis including GRADE qualification. Journal of sports sciences. 2023
- 2Tyrosine for the treatment of phenylketonuria and as a cognitive enhancer in healthy individuals: a systematic reviewSource linkedPMIDJongkees BJ, Hommel B, Kuhn S, Colzato LS · Neuroenhancement · 2015
Randomized controlled trials
6- 3On the effects of tyrosine supplementation on interference control in a randomized, double-blind placebo-control trialNeeds reviewPMIDStock AK, Colzato L, Beste C · European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology · 2018
Stock AK, Colzato L, Beste C. On the effects of tyrosine supplementation on interference control in a randomized, double-blind placebo-control trial. European neuropsychopharmacology : the journal of the European College of Neuropsychopharmacology. 2018
- 4Effects of l-Tyrosine on working memory and inhibitory control are determined by DRD2 genotypes: A randomized controlled trialNeeds reviewPMIDColzato LS, Steenbergen L, Sellaro R et al. · Cortex; a journal devoted to the study of the nervous system and behavior · 2016
Colzato LS, Steenbergen L, Sellaro R et al.. Effects of l-Tyrosine on working memory and inhibitory control are determined by DRD2 genotypes: A randomized controlled trial. Cortex; a journal devoted to the study of the nervous system and behavior. 2016
- 5Tyrosine improves working memory in a multitasking environmentSource linkedPMIDColzato LS, Jongkees BJ, Sellaro R, Hommel B · Pharmacol Biochem Behav · 2013
- 6Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training courseNeeds reviewPMIDDeijen JB et al. · Brain Res Bull · 1999
Tyrosine supplementation improved cognitive task performance and reduced blood pressure in military cadets after demanding combat training
- 7Tyrosine reverses a cold-induced working memory deficit in humansNeeds reviewPMIDShurtleff D et al. · Pharmacol Biochem Behav · 1994
Tyrosine significantly improved matching accuracy at the longest delay interval most affected by cold exposure
- 8Treatment of narcolepsy with L-tyrosine: double-blind placebo-controlled trialNeeds reviewPMIDElwes RD, Crewes H, Chesterman LP et al. · Lancet (London, England) · 1989
Elwes RD, Crewes H, Chesterman LP et al.. Treatment of narcolepsy with L-tyrosine: double-blind placebo-controlled trial. Lancet (London, England). 1989
Reviews & position papers
7- 9O-(2-[(18)F]fluoroethyl)-L-tyrosine-PET-guided versus contrast-enhanced T1-weighted MRI-guided re-irradiation in patients with recurrent glioblastoma (GLIAA/NOA-10 ARO2013-01): a multicentre, open-label, randomised trialNeeds reviewPMIDGrosu AL, Weber WA, Graf E et al. · The Lancet. Oncology · 2026
Grosu AL, Weber WA, Graf E et al.. O-(2-[(18)F]fluoroethyl)-L-tyrosine-PET-guided versus contrast-enhanced T1-weighted MRI-guided re-irradiation in patients with recurrent glioblastoma (GLIAA/NOA-10 ARO2013-01): a multicentre, open-label, randomised trial. The Lancet. Oncology. 2026
- 10Amino acid supplementation in mitochondrial aminoacyl-tRNA synthetase defects: two case reports of tyrosine supplementation in YARS2-associated disease and a review of the literatureNeeds reviewPMIDFerrera G, Segre G, Lamantea E et al. · Frontiers in pediatrics · 2025
Ferrera G, Segre G, Lamantea E et al.. Amino acid supplementation in mitochondrial aminoacyl-tRNA synthetase defects: two case reports of tyrosine supplementation in YARS2-associated disease and a review of the literature. Frontiers in pediatrics. 2025
- 11Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands--A reviewNeeds reviewPMIDJongkees BJ et al. · J Psychiatr Res · 2015
Tyrosine acutely counteracts decrements in working memory and information processing induced by demanding conditions like extreme weather or cognitive load
- 12Tyrosine for Mitigating Stress and Enhancing Performance in Healthy Adult Humans, a Rapid Evidence Assessment of the LiteratureNeeds reviewPMIDAttipoe S et al. · J Mil Med · 2015
Weak recommendation in favor of tyrosine for cognitive stress; all 10 RCTs and 4 controlled trials showed positive effect on cognition under stress
- 13LncRNA NALT interaction with NOTCH1 promoted cell proliferation in pediatric T cell acute lymphoblastic leukemiaNeeds reviewPMIDWang Y, Wu P, Lin R et al. · Scientific reports · 2015
Wang Y, Wu P, Lin R et al.. LncRNA NALT interaction with NOTCH1 promoted cell proliferation in pediatric T cell acute lymphoblastic leukemia. Scientific reports. 2015
- 14Tyrosine, phenylalanine, and catecholamine synthesis and function in the brainNeeds reviewPMIDFernstrom JD, Fernstrom MH · J Nutr · 2007
Tyrosine hydroxylase is the rate-limiting enzyme converting tyrosine to L-DOPA, then to dopamine, norepinephrine, and epinephrine
- 15Review of L-tyrosine confirming its safe human use as an adjuvantNeeds reviewPMIDHoffer LJ · J Food Biochem · 2002
L-tyrosine appears safe with no signs of toxicity or genotoxicity in preclinical studies; well tolerated in clinical trials
Reference material
2- 16McAllister MJ, Martaindale MH, Dillard CC et al.. 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. Stress (Amsterdam, Netherlands). 2024Source linkedPMID
- 17Blachier F, Andriamihaja M. Effects of the L-tyrosine-derived bacterial metabolite p-cresol on colonic and peripheral cells. Amino acids. 2022Source linkedPMID
Keep exploring
Deep dives & adjacent profiles.
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
L-Tyrosine in NutriStack.
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