Throughout the experiment, they completed a battery of performance tests every 90 minutes, including psychomotor function, vigilance, and auditory attention. Compared to the placebo, tyrosine blunted the decline in performance that resulted from sustained work and sleep deprivation. The effects of tyrosine lasted about three hours. No significant side effects were seen.
Tyrosine is a precursor for the catecholamine norepinephrine.
Under conditions of stress, when the release of catecholamines from neurons is increased, the requirement for tyrosine also increases. Of course, chronic treatment with large doses of tyrosine may not be entirely safe, either. However, the results of the present study suggest that tyrosine may be considered for occasional use as a performance-enhancing agent. Neri DF, et al. The effects of tyrosine on cognitive performance during extended wakefulness.