Acetyl L-Tyrosine is a modified, more soluble form of the amino acid L-Tyrosine. L-Tyrosine serves as a direct precursor to catecholamine neurotransmitters, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). The rationale for using Acetyl L-Tyrosine to support the "Epinephrine body system" is based on its role in the biochemical pathway leading to epinephrine synthesis. Several studies have shown that under conditions of acute stress, supplementation with L-Tyrosine can help maintain cognitive performance, likely by supporting catecholamine levels. However, direct evidence that Acetyl L-Tyrosine specifically increases epinephrine levels or supports the adrenergic system in humans is limited. Most available studies have used L-Tyrosine (not the acetylated form), and data on Acetyl L-Tyrosine's bioavailability and efficacy are less robust. While the theoretical basis is scientifically sound, and there is some evidence for L-Tyrosine's effects in stress and cognitive performance, the scientific validation for Acetyl L-Tyrosine's use specifically to support epinephrine or the "Epinephrine body system" is modest. Thus, it earns a score of 2 out of 5 for evidence quality.