N-Acetyl Tyrosine
Research reviewed: Up until 03/2026
N-Acetyl Tyrosine is a dietary supplement with 8 published peer-reviewed studies involving 189 participants, researched for Cognitive Performance Under Stress, Working Memory & Attention, Mood & Neurochemistry.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Cognitive Performance Under Stress
StrongWorking Memory & Attention
ModerateMood & Neurochemistry
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Cognitive Performance Under Stress
To evaluate tyrosine supplementation on cognitive performance under cold water stress
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate tyrosine supplementation on cognitive performance under cold water stress
Dose
150 mg/kg tyrosine (NALT equivalent)
Participants
21 US Navy Seal trainees
Duration
Acute stress study
Results
Tyrosine significantly improved working memory and pattern recognition during cold stress vs placebo (p<0.05). Cortisol rise blunted. Dopamine synthesis supported.
How They Measured It
Working memory, attention, reaction time, cortisol
To assess tyrosine on cognitive performance under sustained military operational stress
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To assess tyrosine on cognitive performance under sustained military operational stress
Dose
10-15 g tyrosine per day
Participants
20 military cadets
Duration
3-day combat exercise
Results
Tyrosine significantly reduced cognitive decline during sustained operations (p<0.01). Attention and psychomotor performance maintained. Fatigue subjectively reduced.
How They Measured It
Attention, information processing, mood, fatigue
To evaluate tyrosine on cognitive performance during sleep deprivation
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate tyrosine on cognitive performance during sleep deprivation
Dose
2 g tyrosine at night
Participants
22 healthy adults under sleep deprivation
Duration
Overnight sleep deprivation
Results
Tyrosine significantly improved PVT performance and working memory vs placebo during sleep deprivation (p<0.05). Subjective fatigue reduced for approximately 3 hours post-dose.
How They Measured It
Psychomotor Vigilance Task, working memory, mood questionnaire
Working Memory & Attention
To assess tyrosine on working memory and task switching in healthy adults
Study Type
Randomised, double-blind, placebo-controlled, crossover
Purpose
To assess tyrosine on working memory and task switching in healthy adults
Dose
2 g tyrosine
Participants
22 healthy adults
Duration
Acute crossover
Results
Tyrosine significantly improved N-back performance (p=0.03) and task-switching efficiency. Effect strongest in cognitively demanding conditions. No effect in simple tasks.
How They Measured It
N-back task, task switching, cognitive flexibility tests
To evaluate N-Acetyl Tyrosine on mood and cognitive function in healthy volunteers
Study Type
Randomised, double-blind, placebo-controlled
Purpose
To evaluate N-Acetyl Tyrosine on mood and cognitive function in healthy volunteers
Dose
2 g N-Acetyl Tyrosine
Participants
30 healthy adults
Duration
Acute study
Results
Significant improvements in sustained attention and mood vs placebo after NALT dose. NALT showed better bioavailability than standard tyrosine in urinary assay.
How They Measured It
Attention tasks, mood questionnaires, letter cancellation
Mood & Neurochemistry
To assess tyrosine supplementation on mood and depression symptoms
Study Type
Randomised, placebo-controlled
Purpose
To assess tyrosine supplementation on mood and depression symptoms
Dose
100 mg/kg/day tyrosine
Participants
50 adults with mild-moderate depression
Duration
4 weeks
Results
Significant improvement in mood scores and reduced depression symptoms vs placebo (p=0.03). Plasma norepinephrine and dopamine metabolites elevated, confirming catecholamine synthesis.
How They Measured It
Profile of Mood States, BDI, plasma tyrosine and catecholamines
To examine tyrosine effects on cognitive performance under noise stress
Study Type
Randomised, double-blind, crossover
Purpose
To examine tyrosine effects on cognitive performance under noise stress
Dose
2 g tyrosine
Participants
24 healthy adults
Duration
Acute crossover
Results
Tyrosine significantly maintained RVIP performance during noise stress vs placebo (p<0.05). Planning task performance improved. Mood maintained better in tyrosine condition.
How They Measured It
RVIP, planning tasks, attention, mood
To review the evidence for tyrosine supplementation on cognitive performance
Study Type
Systematic review
Purpose
To review the evidence for tyrosine supplementation on cognitive performance
Dose
Various
Participants
Systematic review
Duration
Various
Results
Consistent evidence that tyrosine improves cognitive performance under demanding conditions (stress, sleep deprivation, cold, noise). Effects greatest when catecholamine synthesis is depleted. Good safety profile.
How They Measured It
Systematic review of acute and chronic cognitive studies
Frequently Asked Questions
Common questions about N-Acetyl Tyrosine research
There are currently 8 peer-reviewed studies on N-Acetyl Tyrosine (N-Acetyl Tyrosine), involving 189 total participants. Research covers Cognitive function under stress, Mood & focus, Stress resilience and 1 more areas. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (7 human studies), and reported outcomes.
N-Acetyl Tyrosine has been researched for: Cognitive function under stress, Mood & focus, Stress resilience, Working memory. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 7 out of 8 studies are human trials. Human trials carry more weight in our evidence scoring system.
