Scientific Effect
N-Acetyl L-Tyrosine is a precursor for important neurotransmitters. Supplementation may improved cognitive ability, especially in stressful conditions.
Clinical Study
Separation-induced body weight loss, impairment in alternation behavior, and autonomic tone: effects of tyrosine.
Results
"Tyrosine might be a potential therapy for cognitive and mood problems associated with the maintenance of a reduced body weight in the treatment of obesity and in the extreme case of anorexia nervosa."
Study Citation
Hao, S., Avraham, Y., Bonne, O., & Berry, E. M. (2001). Separation-induced body weight loss, impairment in alternation behavior, and autonomic tone: effects of tyrosine. Pharmacology Biochemistry and Behavior, 68(2), 273-281.
LinkClinical Study
Although less effective than D-amphetamine, tyrosine improved performance on several tests. We conclude that all drugs tested improved at least some aspects of cognitive and motor performance after sleep deprivation.
Results
"Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on cognitive and motor performance deficits during sleep deprivation."
Study Citation
Magill, R. A., Waters, W. F., Bray, G. A., Volaufova, J., Smith, S. R., Lieberman, H. R., ... & Ryan, D. H. (2003). Effects of tyrosine, phentermine, caffeine D-amphetamine, and placebo on cognitive and motor performance deficits during sleep deprivation. Nutritional neuroscience, 6(4), 237-246.
LinkClinical Study
...tyrosine may sustain working memory when competing requirements to perform other tasks simultaneously degrade performance, and that supplemental tyrosine may be appropriate for maintaining performance...
Results
"Tyrosine improves working memory in a multitasking environment."
Study Citation
Thomas, J. R., Lockwood, P. A., Singh, A., & Deuster, P. A. (1999). Tyrosine improves working memory in a multitasking environment. Pharmacology Biochemistry and Behavior, 64(3), 495-500.
Link