Evidence supporting the use of: L-tyrosine
For the body system: Sympathetic Nervous System

Links: Go back one page, Tool main page, Ingredients list, Health conditions list, Body systems list

Table of Contents

Synopsis

Source of validity: Scientific
Rating (out of 5): 3

L-tyrosine is an amino acid that serves as a precursor to catecholamine neurotransmitters, including dopamine, norepinephrine, and epinephrine. These neurotransmitters play central roles in the function of the sympathetic nervous system (SNS), which is responsible for the "fight or flight" response. Scientific interest in L-tyrosine as a supplement comes from its biochemical role: during periods of acute stress or cognitive demand, catecholamine levels can be depleted, and supplemental L-tyrosine may help restore or maintain their synthesis.

Several controlled studies in humans have examined L-tyrosine's effects under physical or psychological stress. For example, research has shown that L-tyrosine supplementation can improve cognitive performance and reduce stress-induced declines in working memory and attention, particularly in environments such as cold exposure, sleep deprivation, or military training. These benefits are believed to be due to L-tyrosine’s ability to support catecholamine production when the sympathetic nervous system is highly active.

However, evidence is largely limited to acute, extreme stress scenarios rather than general day-to-day support of the SNS. The overall quality and quantity of studies are moderate, and there is insufficient evidence to recommend L-tyrosine for routine SNS support in healthy individuals.

In summary, the use of L-tyrosine to support the sympathetic nervous system is supported by plausible scientific mechanisms and some human studies, but the strength of evidence is moderate and context-specific.

More about l-tyrosine
More about Sympathetic Nervous System