Supplement

L-Tyrosine

L-tyrosine is an amino acid your body uses to build dopamine, norepinephrine and adrenaline, chemical messengers that shape alertness and the stress response. People mostly look at it for exercise in hot weather, but the evidence is very limited: studies found no clear difference in aerobic performance, and alertness was much the same in a warm-environment soccer test. Those studies were small, under 35 people, so a benefit can't be ruled out.

Sources: PMID 25326727

Updated 30 September 2026
How we grade
25 studies cited

Best evidence: Grade C
Conditions studied: 23
Outcomes: 182
Graded outcomes: 00714

Evidence by condition

Strong
Moderate
Limited
Very limited

23 conditions

Weight Loss & Maintenance

Weight Loss & Maintenance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Impulse Control Small Increase	Improves (the measure goes up)	Small effect	1 study	22 people
Studies that measured impulse control Eating to stop: tyrosine supplementation enhances inhibitory control but not response executionNeuropsychologia · PMID 24433977
	Subjective Well-Being	Improves (the measure goes up)			22 people

Metabolic Health

Metabolic Health: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Studies	People
	Adrenaline Mixed effect			32 people
	Heart Rate	Improves (the measure goes down)	5 studies	26 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Blood glucose	Improves (the measure goes down)	1 study	14 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Dopamine	Improves (the measure goes up)	1 study	20 people
Studies that measured dopamine Effects of tyrosine and tryptophan ingestion on plasma catecholamine and 3,4-dihydroxyphenylacetic acid concentrationsJ Clin Endocrinol Metab · PMID 6885965
	Renin Activity	Improves (the measure goes up)	1 study	12 people
Studies that measured renin activity The influence of oral tyrosine and tryptophan feeding on plasma catecholamines in manAm J Clin Nutr · PMID 6351587
	Blood Lactate (Exercise)	Changes; see studies		14 people
	Blood Pressure	Improves (the measure goes down)		12 people
	Noradrenaline	Improves (the measure goes up)		32 people

General Athletic Performance

Adrenaline
Working Memory: improves
Heart Rate: improves

General Athletic Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Studies	People
	Adrenaline Mixed effect			14 people
	Working Memory	Improves (the measure goes up)	6 studies	15 people
Studies that measured working memory Effect of tyrosine on cognitive function and blood pressure under stressBrain Res Bull · PMID 8293316 Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in AgingNutrients · PMID 29168741 Tyrosine reverses a cold-induced working memory deficit in humansPharmacol Biochem Behav · PMID 8029265 Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training courseBrain Res Bull · PMID 10230711 The effects of tyrosine on cognitive performance during extended wakefulnessAviat Space Environ Med · PMID 7794222 Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humansBrain Res Bull · PMID 2736402
	Heart Rate	Improves (the measure goes down)	5 studies	14 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Alertness	Improves (the measure goes up)	1 study	15 people
Studies that measured alertness Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environmentEur J Appl Physiol · PMID 25326727
	Blood glucose	Improves (the measure goes down)	1 study	34 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Dopamine	Improves (the measure goes up)	1 study	14 people
	Reaction Time	Improves (the measure goes up)	1 study	15 people
	Adrenocorticotropic Hormone	Improves (the measure goes up)		20 people
	Aerobic Exercise Metrics	Improves (the measure goes up)		20 people
	Blood Lactate (Exercise)	Changes; see studies		34 people
	Cortisol	Improves (the measure goes down)		20 people
	Fatigue Symptoms	Improves (the measure goes down)		20 people
	Muscular Endurance	Improves (the measure goes up)		35 people
	Noradrenaline	Improves (the measure goes up)		14 people
	Power Output	Improves (the measure goes up)		14 people
	Strength	Improves (the measure goes up)		35 people
	Subjective Well-Being	Improves (the measure goes up)		20 people

Anaerobic Exercise Performance

Adrenaline
Heart Rate: improves
Blood glucose: improves

Anaerobic Exercise Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Studies	People
	Adrenaline Mixed effect			14 people
	Heart Rate	Improves (the measure goes down)	5 studies	14 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Blood glucose	Improves (the measure goes down)	1 study	34 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Dopamine	Improves (the measure goes up)	1 study	14 people
Studies that measured dopamine Effects of tyrosine and tryptophan ingestion on plasma catecholamine and 3,4-dihydroxyphenylacetic acid concentrationsJ Clin Endocrinol Metab · PMID 6885965
	Adrenocorticotropic Hormone	Improves (the measure goes up)		20 people
	Aerobic Exercise Metrics	Improves (the measure goes up)		20 people
	Blood Lactate (Exercise)	Changes; see studies		34 people
	Cortisol	Improves (the measure goes down)		20 people
	Fatigue Symptoms	Improves (the measure goes down)		20 people
	Muscular Endurance	Improves (the measure goes up)		20 people
	Noradrenaline	Improves (the measure goes up)		14 people
	Power Output	Improves (the measure goes up)		14 people
	Strength	Improves (the measure goes up)		20 people

Soccer Performance

Adrenaline
Heart Rate: improves
Alertness: improves

Soccer Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Studies	People
	Adrenaline Mixed effect			14 people
	Heart Rate	Improves (the measure goes down)	5 studies	22 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Alertness	Improves (the measure goes up)	1 study	8 people
Studies that measured alertness Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environmentEur J Appl Physiol · PMID 25326727
	Blood glucose	Improves (the measure goes down)	1 study	14 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Dopamine	Improves (the measure goes up)	1 study	14 people
Studies that measured dopamine Effects of tyrosine and tryptophan ingestion on plasma catecholamine and 3,4-dihydroxyphenylacetic acid concentrationsJ Clin Endocrinol Metab · PMID 6885965
	Aerobic Exercise Metrics	Improves (the measure goes up)		8 people
	Blood Lactate (Exercise)	Changes; see studies		14 people
	Noradrenaline	Improves (the measure goes up)		14 people
	Power Output	Improves (the measure goes up)		14 people
	Vigor/Activity	Improves (the measure goes up)		8 people

Fatigue

Motor Control: improves
Working Memory: improves
Sleep Deprivation Symptoms: improves

Fatigue: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Motor Control Small Improvement	Improves (the measure goes up)	Small effect		18 people
	Working Memory	Improves (the measure goes up)		6 studies	18 people
Studies that measured working memory Effect of tyrosine on cognitive function and blood pressure under stressBrain Res Bull · PMID 8293316 Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in AgingNutrients · PMID 29168741 Tyrosine reverses a cold-induced working memory deficit in humansPharmacol Biochem Behav · PMID 8029265 Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training courseBrain Res Bull · PMID 10230711 The effects of tyrosine on cognitive performance during extended wakefulnessAviat Space Environ Med · PMID 7794222 Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humansBrain Res Bull · PMID 2736402
	Sleep Deprivation Symptoms	Improves (the measure goes down)			18 people

Narcolepsy

Attention: improves
Narcolepsy Symptoms: improves
Sleep Latency: improves

Narcolepsy: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Attention Small Improvement	Improves (the measure goes up)	Small effect		10 people
	Narcolepsy Symptoms	Improves (the measure goes down)		1 study	10 people
Studies that measured narcolepsy symptoms Treatment of narcolepsy with L-tyrosine: double-blind placebo-controlled trialLancet · PMID 2572797
	Sleep Latency	Improves (the measure goes down)			10 people

Cognitive Improvement

Alertness
Adrenocorticotropic Hormone
Working Memory: improves

Cognitive Improvement: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Alertness No effect		NoneNo effect	1 study	23 people
Studies that measured alertness Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environmentEur J Appl Physiol · PMID 25326727
	Adrenocorticotropic Hormone No effect		NoneNo effect		20 people
	Working Memory	Improves (the measure goes up)		6 studies	140 people
Studies that measured working memory Effect of tyrosine on cognitive function and blood pressure under stressBrain Res Bull · PMID 8293316 Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in AgingNutrients · PMID 29168741 Tyrosine reverses a cold-induced working memory deficit in humansPharmacol Biochem Behav · PMID 8029265 Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training courseBrain Res Bull · PMID 10230711 The effects of tyrosine on cognitive performance during extended wakefulnessAviat Space Environ Med · PMID 7794222 Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humansBrain Res Bull · PMID 2736402
	Depression Symptoms	Improves (the measure goes down)		1 study	21 people
Studies that measured depression symptoms Tyrosine for depression: a double-blind trialJ Affect Disord · PMID 2142699
	Reaction Time	Improves (the measure goes up)		1 study	35 people
Studies that measured reaction time Dietary tyrosine benefits cognitive and psychomotor performance during body coolingPhysiol Behav · PMID 17078981
	Attention	Improves (the measure goes up)			57 people
	Blood Pressure	Improves (the measure goes down)			65 people
	Cortisol	Improves (the measure goes down)			40 people
	Fatigue Symptoms	Improves (the measure goes down)			21 people
	Motor Control	Improves (the measure goes up)			18 people
	Muscular Endurance	Improves (the measure goes up)			15 people
	Noradrenaline	Improves (the measure goes up)			8 people
	Processing Accuracy	Improves (the measure goes up)			20 people
	Processing Speed	Improves (the measure goes up)			20 people
	Sleep Deprivation Symptoms	Improves (the measure goes down)			18 people
	Strength	Improves (the measure goes up)			15 people
	Stress Signs and Symptoms	Improves (the measure goes down)			21 people
	Subjective Well-Being	Improves (the measure goes up)			21 people
	Vigor/Activity	Improves (the measure goes up)			8 people

Warm Or Hot Weather Exercise Performance

Aerobic Exercise Metrics
Heart Rate: improves
Rating of Perceived Exertion: improves

Warm Or Hot Weather Exercise Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Aerobic Exercise Metrics No effect		NoneNo effect		31 people
	Heart Rate	Improves (the measure goes down)		5 studies	31 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Rating of Perceived Exertion	Improves (the measure goes up)		3 studies	23 people
Studies that measured rating of perceived exertion No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm EnvironmentMed Sci Sports Exerc · PMID 31834099 Failure of oral tyrosine supplementation to improve exercise performance in the heatMed Sci Sports Exerc · PMID 24389518 Oral tyrosine supplementation improves exercise capacity in the heatEur J Appl Physiol · PMID 21437603
	Alertness	Improves (the measure goes up)		1 study	8 people
Studies that measured alertness Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environmentEur J Appl Physiol · PMID 25326727
	Blood glucose	Improves (the measure goes down)		1 study	8 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Body Temperature	Improves (the measure goes up)		1 study	16 people
	Blood Lactate (Exercise)	Changes; see studies			8 people
	Power Output	Improves (the measure goes up)			15 people
	Vigor/Activity	Improves (the measure goes up)			8 people
	Weight	Improves (the measure goes down)			7 people

General Cardiovascular Health

Blood Pressure
Heart Rate: improves
Body Temperature: improves

General Cardiovascular Health: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Blood Pressure No effect		NoneNo effect		40 people
	Heart Rate	Improves (the measure goes down)		5 studies	42 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Body Temperature	Improves (the measure goes up)		1 study	18 people
Studies that measured body temperature Oral L-Tyrosine Supplementation Improves Core Temperature Maintenance in Older AdultsMed Sci Sports Exerc · PMID 31609301
	Reaction Time	Improves (the measure goes up)		1 study	20 people
Studies that measured reaction time Dietary tyrosine benefits cognitive and psychomotor performance during body coolingPhysiol Behav · PMID 17078981
	Cortisol	Improves (the measure goes down)			20 people
	Pulse Pressure	Improves (the measure goes up)			20 people

Aerobic Exercise Performance

Adrenocorticotropic Hormone
Heart Rate: improves
Rating of Perceived Exertion: improves

Aerobic Exercise Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Adrenocorticotropic Hormone No effect		NoneNo effect		20 people
	Heart Rate	Improves (the measure goes down)		5 studies	9 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Rating of Perceived Exertion	Improves (the measure goes up)		3 studies	9 people
Studies that measured rating of perceived exertion No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm EnvironmentMed Sci Sports Exerc · PMID 31834099 Failure of oral tyrosine supplementation to improve exercise performance in the heatMed Sci Sports Exerc · PMID 24389518 Oral tyrosine supplementation improves exercise capacity in the heatEur J Appl Physiol · PMID 21437603
	Blood glucose	Improves (the measure goes down)		1 study	29 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Aerobic Exercise Metrics	Improves (the measure goes up)			29 people
	Blood Lactate (Exercise)	Changes; see studies			29 people
	Cortisol	Improves (the measure goes down)			20 people
	Fatigue Symptoms	Improves (the measure goes down)			20 people
	Free Fatty Acids	Improves (the measure goes up)			9 people
	Muscular Endurance	Improves (the measure goes up)			20 people
	Oxygen Uptake	Improves (the measure goes up)			9 people
	Strength	Improves (the measure goes up)			20 people

Cycling Performance

Aerobic Exercise Metrics
Heart Rate: improves
Rating of Perceived Exertion: improves

Cycling Performance: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People
	Aerobic Exercise Metrics No effect		NoneNo effect		16 people
	Heart Rate	Improves (the measure goes down)		5 studies	16 people
Studies that measured heart rate Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol · 1985 · PMID 12381742 L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196 Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375 Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894 Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
	Rating of Perceived Exertion	Improves (the measure goes up)		3 studies	16 people
Studies that measured rating of perceived exertion No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm EnvironmentMed Sci Sports Exerc · PMID 31834099 Failure of oral tyrosine supplementation to improve exercise performance in the heatMed Sci Sports Exerc · PMID 24389518 Oral tyrosine supplementation improves exercise capacity in the heatEur J Appl Physiol · PMID 21437603
	Blood glucose	Improves (the measure goes down)		1 study	9 people
Studies that measured blood glucose Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
	Blood Lactate (Exercise)	Changes; see studies			9 people
	Free Fatty Acids	Improves (the measure goes up)			9 people
	Oxygen Uptake	Improves (the measure goes up)			9 people
	Power Output	Improves (the measure goes up)			7 people
	Weight	Improves (the measure goes down)			7 people

High Blood Pressure

Blood Pressure
Heart Rate: improves
Noradrenaline: improves

High Blood Pressure: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Blood Pressure No effect		NoneNo effect		13 people
Heart Rate	Improves (the measure goes down)		5 studies	13 people
Noradrenaline	Improves (the measure goes up)			13 people

Memory Improvement

Blood Pressure
Working Memory: improves
Noradrenaline: improves

Memory Improvement: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Blood Pressure No effect		NoneNo effect		8 people
Working Memory	Improves (the measure goes up)		6 studies	16 people
Noradrenaline	Improves (the measure goes up)			8 people

Muscle Size Strength

Adrenocorticotropic Hormone
Aerobic Exercise Metrics: improves
Blood Lactate (Exercise): changes; see studies

Muscle Size Strength: outcomes studied for L-Tyrosine
Outcome	Effect	Size	People
Adrenocorticotropic Hormone No effect		NoneNo effect	20 people
Aerobic Exercise Metrics	Improves (the measure goes up)		20 people
Blood Lactate (Exercise)	Changes; see studies		20 people
Cortisol	Improves (the measure goes down)		20 people
Fatigue Symptoms	Improves (the measure goes down)		20 people
Muscular Endurance	Improves (the measure goes up)		20 people
Strength	Improves (the measure goes up)		20 people
Subjective Well-Being	Improves (the measure goes up)		20 people

Parkinson's Disease

Blood Pressure
Heart Rate: improves
Noradrenaline: improves

Parkinson's Disease: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Blood Pressure No effect		NoneNo effect		40 people
Heart Rate	Improves (the measure goes down)		5 studies	40 people
Noradrenaline	Improves (the measure goes up)			40 people
Oxygen Uptake	Improves (the measure goes up)			40 people

Running Performance

Adrenocorticotropic Hormone
Blood glucose: improves
Aerobic Exercise Metrics: improves

Running Performance: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Adrenocorticotropic Hormone No effect		NoneNo effect		20 people
Blood glucose	Improves (the measure goes down)		1 study	20 people
Aerobic Exercise Metrics	Improves (the measure goes up)			20 people
Blood Lactate (Exercise)	Changes; see studies			20 people
Cortisol	Improves (the measure goes down)			20 people
Fatigue Symptoms	Improves (the measure goes down)			20 people
Muscular Endurance	Improves (the measure goes up)			20 people
Strength	Improves (the measure goes up)			20 people

Schizophrenia

Memory
Schizophrenia symptoms: improves

Schizophrenia: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Memory No effect		NoneNo effect		11 people
	Schizophrenia symptoms	Improves (the measure goes down)		1 study	11 people

Warm- or Hot-Weather Exercise Performance

Aerobic Exercise Metrics
Heart Rate: changes; see studies
Rating of Perceived Exertion: improves

Warm- or Hot-Weather Exercise Performance: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Aerobic Exercise Metrics No effect		NoneNo effect		31 people
Heart Rate	Changes; see studies		5 studies	31 people
Rating of Perceived Exertion	Improves (the measure goes up)		3 studies	23 people
Alertness	Improves (the measure goes up)		1 study	8 people
Blood glucose	Changes; see studies		1 study	8 people
Body Temperature	Improves (the measure goes up)		1 study	16 people
Blood Lactate (Exercise)	Changes; see studies			8 people
Power Output	Improves (the measure goes up)			15 people
Vigor/Activity	Improves (the measure goes up)			8 people
Weight	Changes; see studies			7 people

Muscle Size & Strength

Adrenocorticotropic Hormone
Aerobic Exercise Metrics: improves
Blood Lactate (Exercise): changes; see studies

Muscle Size & Strength: outcomes studied for L-Tyrosine
Outcome	Effect	Size	People
Adrenocorticotropic Hormone No effect		NoneNo effect	20 people
Aerobic Exercise Metrics	Improves (the measure goes up)		20 people
Blood Lactate (Exercise)	Changes; see studies		20 people
Cortisol	Changes; see studies		20 people
Fatigue Symptoms	Changes; see studies		20 people
Muscular Endurance	Improves (the measure goes up)		20 people
Strength	Improves (the measure goes up)		20 people
Subjective Well-Being	Improves (the measure goes up)		20 people

Mental Resilience

Working Memory: improves
Heart Rate: improves
Depression Symptoms: improves

Mental Resilience: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Working Memory	Improves (the measure goes up)		6 studies	23 people
Heart Rate	Improves (the measure goes down)		5 studies	101 people
Depression Symptoms	Improves (the measure goes down)		1 study	78 people
Anger Small Detriment	Worsens (the measure goes up)	Small effect		78 people
Attention	Improves (the measure goes up)			23 people
Cortisol	Improves (the measure goes down)			78 people
Fatigue Symptoms	Improves (the measure goes down)			78 people
Processing Accuracy	Improves (the measure goes up)			23 people
Stress Signs and Symptoms	Improves (the measure goes down)			23 people
Subjective Well-Being	Improves (the measure goes up)			23 people
Vigor/Activity	Improves (the measure goes up)			78 people

Stress

Working Memory: improves
Heart Rate: improves
Depression Symptoms: improves

Stress: outcomes studied for L-Tyrosine
Outcome	Effect	Size	Studies	People
Working Memory	Improves (the measure goes up)		6 studies	23 people
Heart Rate	Improves (the measure goes down)		5 studies	101 people
Depression Symptoms	Improves (the measure goes down)		1 study	78 people
Anger Small Detriment	Worsens (the measure goes up)	Small effect		78 people
Attention	Improves (the measure goes up)			23 people
Blood Pressure	Improves (the measure goes down)			23 people
Cortisol	Improves (the measure goes down)			78 people
Fatigue Symptoms	Improves (the measure goes down)			78 people
Processing Accuracy	Improves (the measure goes up)			23 people
Stress Signs and Symptoms	Improves (the measure goes down)			23 people
Subjective Well-Being	Improves (the measure goes up)			23 people
Vigor/Activity	Improves (the measure goes up)			78 people

Depression

Depression Symptoms: improves

Depression: outcomes studied for L-Tyrosine
Grade	Outcome	Effect	Size	Studies	People	Studies list
	Depression Symptoms	Improves (the measure goes down)		1 study	65 people

Key findings

Impulse ControlWeight Loss & MaintenanceImproves (the measure goes up)
AdrenalineMetabolic Health
Motor ControlFatigueImproves (the measure goes up)

Shop L-Tyrosine

Third-party tested L-Tyrosine products. The evidence above is limited, so read it before you buy.

Grade C

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Studies cited

25 studies from PubMed

Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performanceJ Appl Physiol, 1985 · PMID 12381742
L-tyrosine ameliorates some effects of lower body negative pressure stressPhysiol Behav · PMID 7716196
Oral l-tyrosine supplementation augments the vasoconstriction response to whole-body cooling in older adultsExp Physiol · PMID 28477375
Oral L-Tyrosine Supplementation Improves Core Temperature Maintenance in Older AdultsMed Sci Sports Exerc · PMID 31609301
Dietary tyrosine benefits cognitive and psychomotor performance during body coolingPhysiol Behav · PMID 17078981
Effect of tyrosine on cognitive function and blood pressure under stressBrain Res Bull · PMID 8293316
Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in AgingNutrients · PMID 29168741
Tyrosine reverses a cold-induced working memory deficit in humansPharmacol Biochem Behav · PMID 8029265
Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training courseBrain Res Bull · PMID 10230711
The effects of tyrosine on cognitive performance during extended wakefulnessAviat Space Environ Med · PMID 7794222
Effect of tyrosine ingestion on cognitive and physical performance utilising an intermittent soccer performance test (iSPT) in a warm environmentEur J Appl Physiol · PMID 25326727
No Influence of Low-, Medium-, or High-Dose Tyrosine on Exercise in a Warm EnvironmentMed Sci Sports Exerc · PMID 31834099
Failure of oral tyrosine supplementation to improve exercise performance in the heatMed Sci Sports Exerc · PMID 24389518
Oral tyrosine supplementation improves exercise capacity in the heatEur J Appl Physiol · PMID 21437603
Ingestion of tyrosine: effects on endurance, muscle strength, and anaerobic performanceInt J Sport Nutr Exerc Metab · PMID 16089275
Effects of tyrosine and tryptophan ingestion on plasma catecholamine and 3,4-dihydroxyphenylacetic acid concentrationsJ Clin Endocrinol Metab · PMID 6885965
The influence of oral tyrosine and tryptophan feeding on plasma catecholamines in manAm J Clin Nutr · PMID 6351587
Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humansBrain Res Bull · PMID 2736402
The catecholamine neurotransmitter precursor tyrosine increases anger during exposure to severe psychological stressPsychopharmacology · PMID 25220844
Effects of Tyrosine on Parkinson's Disease: A Randomized, Double-Blind, Placebo-Controlled TrialMov Disord Clin Pract · PMID 30363894
L-tyrosine pharmacotherapy of schizophrenia: preliminary dataClin Neuropharmacol · PMID 8149360
Eating to stop: tyrosine supplementation enhances inhibitory control but not response executionNeuropsychologia · PMID 24433977
Treatment of narcolepsy with L-tyrosine: double-blind placebo-controlled trialLancet · PMID 2572797
Chronic dietary tyrosine supplements do not affect mild essential hypertensionHypertension · PMID 3891616
Tyrosine for depression: a double-blind trialJ Affect Disord · PMID 2142699