Tyrosine
Small crossover trials found tyrosine preserved working memory during cold exposure and multitasking, and improved some tasks after sleep loss. Most exercise trials found no change in endurance, strength or power. A trial in depression found no antidepressant effect. In adults over 60, higher doses were followed by worse working memory.
Add to Bio HackChecked 2026-11-09
- Status
- Dietary supplement and food ingredient in the US.
- Also called
- L-tyrosine, N-acetyl L-tyrosine, NALT, TYR
- Taken for
- focus, working memory, stress, sleep deprivation, cold exposure, mood, depression, endurance, pre-workout energy
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Shown to help1
What people take it for, and what was found
Shown to help1
Working memory under stress or heavy demand
Small trials found tyrosine helped working memory under cold, multitasking or sleep loss in healthy young adults, with no effect on soccer decisions in the heat.
The numbers and sources
- Effect
- In 19 volunteers immersed in cold water, tyrosine (300 mg/kg total) raised correct responses on a match-to-sample memory test that had fallen in the cold [1]. In 20 adults given 150 mg/kg, working memory accuracy rose during a multitask battery, with no change on arithmetic, visual or auditory tasks or on a simple task battery [2]. After a night without sleep, 150 mg/kg improved several tests, less than 20 mg D-amphetamine did [3]. In 22 adults, tyrosine reduced task-switching costs [4]. In 8 trained soccer players exercising in the heat, 150 mg/kg did not change soccer decision-making accuracy (86.9% versus 88.6% on placebo) [5]. A review concluded the benefit appears in short, demanding situations and when neurotransmitter function is intact [6].
- Population
- Healthy young adults in single-session crossover trials of 19 to 22 people [1][2][4]; young men after sleep deprivation [3]; trained male soccer players [5].
- Sources
- [1], [2], [3], [4], [6], [5]
- Caveats
- No meta-analysis exists. Each trial is small and measured a different task.
Mixed results1
Endurance in the heat
Small trials found mixed results: one found longer time to exhaustion cycling in the heat, while two others found no change in performance.
The numbers and sources
- Effect
- In 8 men cycling at 30°C, 150 mg/kg tyrosine extended time to exhaustion from 69.2 to 80.3 minutes [7]. In a follow-up with 7 endurance-trained men at 30°C using the same dose, time-trial performance did not differ (34.8 versus 35.2 minutes) [8]. In 8 trained soccer players doing 92 minutes of intermittent sprint cycling at 32°C, 150 mg/kg did not change peak power output (715 versus 724 W) [5].
- Population
- Small groups of trained men [7][8][5].
- Sources
- [7], [8], [5]
- Caveats
- The same group ran both trials and got opposite results with different test formats, a fixed-intensity ride to exhaustion and a self-paced time trial.
Not shown to help2
Endurance, strength and power at normal temperatures
Small trials found no change in endurance, strength or power at normal temperatures, except longer time to exhaustion in one trial after mental fatigue.
The numbers and sources
- Effect
- In 20 men after load carriage, 150 mg/kg did not change treadmill time (118.9 versus 119.2 minutes), stair-stepping power or handgrip [9]. In 9 cyclists, 25 mg/kg did not change time-trial performance after 90 minutes of cycling, while carbohydrate did [10]. In 12 recreational cyclists mentally fatigued by a 60-minute Stroop task, 300 mg/kg extended time to exhaustion at 80% of maximal power from 398.7 to 459.9 seconds (p = 0.008) and slowed the rise in perceived exertion compared with placebo [11].
- Population
- Healthy men and competitive cyclists [9][10]; 12 recreational cyclists [11].
- Sources
- [9], [10], [11]
- Caveats
- Small crossover trials. The mental fatigue trial tested both conditions after the Stroop task, with no rested comparison [11]. The review found little support for exercise benefit [6].
Depression
One 4-week trial found no antidepressant effect over placebo in adults with major depression.
The numbers and sources
- Effect
- In 65 outpatients with major depression, 100 mg/kg a day for 4 weeks showed no antidepressant effect compared with placebo, although it changed a noradrenaline metabolite in urine [12].
- Population
- 65 adults with major depression, compared with imipramine and placebo [12].
- Sources
- [12]
- Caveats
- One trial, 4 weeks long.
Doses studied
Cognitive trials used 150 mg/kg as a single dose, about 10 to 11 g for a 70 kg adult, and the cold study gave two such doses [1][2][3]. Exercise trials used 25 to 150 mg/kg [7][9][10], and 300 mg/kg in mentally fatigued cyclists [11]. The depression trial used 100 mg/kg a day for 4 weeks [12]. A dose-ranging trial in older adults gave 100, 150 or 200 mg/kg [13]. A 4-week safety trial gave 1, 2, 3 or 4 g a day [14].
Risks
Reported risks1
Worse working memory in older adults at higher doses
Small trials found working memory declined at higher single doses in healthy adults aged 60 to 75.
The numbers and sources
- Effect
- In 17 adults aged 60 to 75, plasma tyrosine rose more than in young adults at the same dose, and working memory under load declined as the dose rose from 100 to 200 mg/kg (p = 0.048) [13]. In 24 adults aged 61 to 72, older age was associated with a larger negative effect of tyrosine on proactive response slowing compared with placebo [15].
- Population
- Healthy older adults in crossover trials [13][15].
- Sources
- [13], [15]
- Caveats
- Two small trials from overlapping research teams. Effects were measured after single doses.
Checked, no increase found1
Side effects in 4-week trials
Two 4-week trials found side effects about as common as on placebo, with no dose-related blood test changes up to 4 g a day.
The numbers and sources
- Effect
- At 100 mg/kg a day for 4 weeks, the only side effect that differed significantly between groups was dry mouth with imipramine, not tyrosine [12]. In 30 healthy men given 0, 1, 2, 3 or 4 g a day for 4 weeks each in a crossover, blood tests showed no dose-related abnormalities, no serious adverse events occurred, and mild to moderate events were comparable to placebo [14].
- Population
- 65 adults with depression [12]; 30 healthy adult men [14].
- Sources
- [12], [14]
- Caveats
- Two trials, both 4 weeks long. Most other trials were single sessions and did not report side effects in their abstracts.
Claims tested and not found
- That tyrosine improves endurance. Treadmill time after load carriage did not change [9], cycling time trials did not change [10], a self-paced time trial in the heat did not change [8], and peak power in intermittent sprints in the heat did not change [5].
- That tyrosine treats depression. A 4-week trial found no antidepressant effect compared with placebo [12].
Sources
- Mahoney CR, Castellani J, Kramer FM, et al. Tyrosine supplementation mitigates working memory decrements during cold exposure. Physiology & Behavior. 2007. https://doi.org/10.1016/j.physbeh.2007.05.003
- Thomas JR, Lockwood PA, Singh A, et al. Tyrosine Improves Working Memory in a Multitasking Environment. Pharmacology Biochemistry and Behavior. 1999. https://doi.org/10.1016/s0091-3057(99)00094-5
- Magill RA, Waters WF, Bray GA, et al. Effects of Tyrosine, Phentermine, Caffeine d-amphetamine, and Placebo on Cognitive and Motor Performance Deficits During Sleep Deprivation. Nutritional Neuroscience. 2003. https://doi.org/10.1080/1028415031000120552
- Steenbergen L, Sellaro R, Hommel B, et al. Tyrosine promotes cognitive flexibility: Evidence from proactive vs. reactive control during task switching performance. Neuropsychologia. 2015. https://doi.org/10.1016/j.neuropsychologia.2015.01.022
- Donnan KJ, Williams EL, Stanger N. Tyrosine supplementation is ineffective in facilitating soccer players' physical and cognitive performance during high-intensity intermittent exercise in hot conditions. PLOS ONE. 2025. https://doi.org/10.1371/journal.pone.0317486
- Jongkees BJ, Hommel B, Kühn S, et al. Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands: A review. Journal of Psychiatric Research. 2015. https://doi.org/10.1016/j.jpsychires.2015.08.014
- Tumilty L, Davison G, Beckmann M, et al. Oral tyrosine supplementation improves exercise capacity in the heat. European Journal of Applied Physiology. 2011. https://doi.org/10.1007/s00421-011-1921-4
- Tumilty L, Davison G, Beckmann M, et al. Failure of Oral Tyrosine Supplementation to Improve Exercise Performance in the Heat. Medicine & Science in Sports & Exercise. 2014. https://doi.org/10.1249/mss.0000000000000243
- Sutton EE, Coll MR, Deuster PA. Ingestion of Tyrosine: Effects on Endurance, Muscle Strength, and Anaerobic Performance. International Journal of Sport Nutrition and Exercise Metabolism. 2005. https://doi.org/10.1123/ijsnem.15.2.173
- Chinevere TD, Sawyer RD, Creer AR, et al. Effects of L-tyrosine and carbohydrate ingestion on endurance exercise performance. Journal of Applied Physiology. 2002. https://doi.org/10.1152/japplphysiol.00625.2001
- Solon-Júnior LJF, Boullosa D, Dias CV, et al. Effects of L-Tyrosine Ingestion on Endurance Performance in Mentally Fatigued Cyclists. European Journal of Sport Science. 2026. https://doi.org/10.1002/ejsc.70150
- Gelenberg AJ, Wojcik JD, Falk WE, et al. Tyrosine for depression: a double-blind trial. Journal of Affective Disorders. 1990. https://doi.org/10.1016/0165-0327(90)90017-3
- van de Rest O, Bloemendaal M, de Heus R, et al. Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in Aging. Nutrients. 2017. https://doi.org/10.3390/nu9121279
- Matsumoto H, Miura N, Naito M, et al. Evaluation of the Safety and Tolerability of L-Tyrosine Supplementation in Healthy Adult Men: A Randomized Crossover Trial. Nutrients. 2026. https://doi.org/10.3390/nu18122020
- Bloemendaal M, Froböse MI, Wegman J, et al. Neuro-Cognitive Effects of Acute Tyrosine Administration on Reactive and Proactive Response Inhibition in Healthy Older Adults. eNeuro. 2018. https://doi.org/10.1523/eneuro.0035-17.2018