Premium Grade! Supports Mental Alertness! Healthy Glandular Function! L-Tyrosine is a non-essential amino acid that plays an important role in the production of neurotransmitters dopamine and norepinephrine. In addition, because L-Tyrosine is necessary for the synthesis of thyroid hormone and epinephrine (adrenaline), L-Tyrosine supports healthy glandular function and stress response. Note: Manufacturers continually change product specifications. While we try our best to keep product descriptions up to date, they do not necessarily reflect the latest information available from the manufacturer. We are not responsible for incorrect or outdated product descriptions and/or images.