Acetyl l-tyrosine is an acetylated derivative of the non-essential amino acid l-tyrosine that occurs naturally in the human body. The name comes from the Greek word tyri, which means "cheese," named by a German scientist who found the compound in casein, a cheese-derived protein. The amino acid is non-essential because l-tyrosine can be manufactured in the body from l-phenylalanine. Acetyl l-tyrosine is sold as a dietary supplement around the world and is used by many people who suffer from deficiency, which can lead to various physical and mental health issues. L-tyrosine is well-known for its mood-stabilizing, cognitive-enhancing, and metabolism-boosting effects within the body.
L- tyrosine is a precursor to many compounds essential for normal functioning of the human system. These include the neurotransmitters dopamine, epinephrine, and norepinephrine, which regulate behavior and mood. Having inadequate amounts of l-tyrosine for neurotransmitter production is implicated in conditions such as depression, anxiety, and Parkinson's disease. The thyroid hormones threonine and thyroxinine depend on the amino acid as a precursor, as well, and a deficiency can lead to a sluggish thyroid, and in turn, weight gain and decreased metabolism. The thyroid-boosting effect, along with l-tyrosine's known appetite regulating capabilities, has led to it becoming a popular diet aid and bodybuilding supplement.
Cognition is enhanced by acetyl l-tyrosine because of its interaction with the body's "fight or flight" response. L-tyrosine has specific action in the amygdala portion of the brain, which can increase the heart rate and thus increase glucose stores and delivery of oxygen needed for optimal brain functioning. Increased oxygen delivery to muscles around the body can ease the debilitating symptoms of diseases like chronic fatigue syndrome.
An abundant supply of l-tyrosine can be found in high-protein sources like dairy products, meats, and nuts. When the supplement is made with an added acetyl group, it has more bioavailability, mainly due to regular l-tyrosine being mostly insoluble in water, and it takes a much smaller dose of the amino acid to be effective. L-tyrosine and l-phenylalanine are dependent on each other for synthesis, so many people take both supplements together to ensure adequate levels of each amino acid. The recommended dosage of acetyl l-tyrosine is between 150 mg and 700 mg per day, and may need to adjusted if side effects like insomnia and rapid heartbeat are present. It is recommended that supplementation with acetyl l-tyrosine be monitored by a physician.