May help shield the brain from the adverse effects of stress

  • Supports performance during prolonged, high-stress work
  • Enhances cognitive function and alertness during multitasking and sleep deprivation
  • AOR offers a potent and effective daily dose
Gluten Free

$49.31 or subscribe and save 20%

Out of stock

L-Tyrosine is an amino acid found in wheat germ, oats, dairy products, pork and poultry. It is a precursor for the neurotransmitters epinephrine, norepinephrine, and dopamine, which are all essential for mood, cognitive function and central nervous system function. The most prevalent usage for supplemental L-tyrosine appears to be the enhancement of cognitive function and alertness under conditions of environmental stress such as sleep deprivation, multi-tasking in the workplace, and functioning at high altitudes and/or cold temperatures. It is noteworthy to mention that a high percentage of the studies done on L-tyrosine are conducted by the military looking to enhance focus and attention in their personnel. Clinical trials with L-tyrosine have also been conducted with respect to attention deficit disorder (ADD) with good results. L-Tyrosine is also used by the body to make thyroid hormones as well as melanin, the skin and hair pigment.

L-Tyrosine is ideal for those who are required to work long hours under stressful conditions, those whose lifestyles or work require a high degree of multitasking, those who experience prolonged physical and mental stress, students, and those who have difficulty concentrating such as in ADD.

AOR Advantage

AOR’s L-Tyrosine offers a potent and effective daily dose of this important amino acid.




L-Tyrosine is a master precursor amino acid used to synthesize neurotransmitters involved in memory, mood and mental processing, including dopamine, epinephrine and norepinephrine. L-Tyrosine helps in the management of both physical and psychological stress, including the stress caused by sleep deprivation and multitasking.


AOR™ guarantees that all ingredients have been declared on the label. Contains no corn, wheat, gluten, nuts, peanuts, sesame seeds, sulphites, mustard, soy, dairy, eggs, fish, shellfish or any animal byproduct.

Adult Dosage

Take six capsules in the morning on an empty stomach, or as directed by a qualified health care practitioner.


Do not use if you are pregnant or breastfeeding, or have the genetic metabolic disorder phenylketonuria (PKU). For prolonged use, consult a health care practitioner. Supplemental L-tyrosine may increase blood pressure or lead to difficulty sleeping in some persons. Consult a health care practitioner prior to use if you have hyperthyroidism, Graves’ disease or active melanoma, or if you are taking dopamine, thyroid hormone medication, contraceptives or other psychoactive medications. Discontinue use if you experience nausea, headache, fatigue, heartburn or joint pain.

Main Applications
  • Physical and mental stress
  • Neurotransmitter function

The information and product descriptions appearing on this website are for information purposes only, and are not intended to provide or replace medical advice to individuals from a qualified health care professional. Consult with your physician if you have any health concerns, and before initiating any new diet, exercise, supplement, or other lifestyle changes.

Serving Size: One Capsule
600 mg

Non-medicinal Ingredients: none. Capsule: hypromellose.

Sleep Deprivation
Military life is one of the few areas of employment in modern society where the work is meant to be as physically and as psychologically taxing on its employees as possible. Soldiers are meant to function under conditions that are often unnaturally stressful, and none more so than those imposed on the pilots of the United States Marine Corps. In a study conducted at the U.S. Naval Aerospace Medical Research Laboratory in Pensacola, Florida, 20 such marine aviators (all males, aged 21-27) volunteered to help determine if tyrosine can improve alertness during periods of sleep deprivation. After being deprived of sleep for 24 hours, the marines taking tyrosine scored markedly higher and made significantly fewer errors in their standardized tests which measured their hand-eye coordination, memory capacity, and comprehensive skills.

High Altitudes and Cold Weather
Hypoxia is the condition whereupon the body’s tissues are deprived of oxygen. This can take place in high altitudes (due to thin air) and extremely cold temperatures (due to constricting arteries). High altitude exposure causes hypobaric hypoxia, and additional exposure to extremely cold temperatures can further exacerbate this cognitive impairment. The bottom biological line is that acutely stressful situations (such as, but not limited to – hypoxia) can deplete brain norepinephrine and dopamine levels, thus disrupting behaviour and performance.

Human studies with tyrosine have been impressive. A series of clinical trials were conducted by the U.S. Army Research Institute of Environmental Medicine in Natick, Montana among soldiers operating at mountainous altitudes of 15,300 feet. They revealed that “tyrosine significantly mitigated many of the decrements in symptoms, mood, and performance induced by [hypobaric hypoxia], including functions believed to be regulated by catecholaminergic neurons such as vigilance, alertness, and anxiety.”

The United States Air Force, for its part, commissioned a study investigating the effectiveness of tyrosine on acute cardiovascular stress. Using a method designed to simulate gravitational stress (orthostasis), subjects who were given tyrosine experienced stabilized pulse pressures and increased central nervous system activity.

Animal Studies: Better Performance Under Stress
Extensive animal studies have revealed some very interesting revelations about tyrosine. In a series of trials, laboratory rats that were pre-treated with tyrosine were subjected to the Porsolt swim test, which is when the rats are placed in an escape-proof tank filled with freezing water. The amount of time that the rats were immobilized by the freezing water was then measured. It was found that the rats that were pre-treated with tyrosine had their immobility time reduced significantly, so much so in fact that the performance levels of these animals matched those that were not exposed to cold-induced stress.

Another type of test called the Morris water maze tested spatial learning and memory in laboratory rats exposed to a simulated height of 19,500 feet for 8 hours. The decrements in performance among the tyrosine-treated animals were only marginal, where as the non-treated animals’ decline in performance was considerable.

ADD or Attention Deficit Disorder (sometimes referred to as attention deficit hyperactivity disorder, or ADHD) can be defined as a persistent pattern of inattention, hyperactivity, and impulsivity, occurring more frequently and severely than is typical in individuals at a comparable level of development. As expected, many diagnoses occur among schoolchildren, and there appears to be some connection between this disorder and the maintenance of adequate levels of certain amino acids, especially phenylalanine, tyrosine, tryptophan, histidine, and isoleucine. In fact, recent data suggest that children with phenylketonuria (PKU) may have an increased prevalence of attentional dysfunction.

The results from studies conducted with tyrosine with specific regard to ADD have been mixed, with their beneficial role being limited to a temporary one. In one noted clinical trial, 12 adults with ADD supplemented with tyrosine for 8 weeks. After 2 weeks, 8 of these subjects showed “marked to moderate” improvements, but after 6 weeks these particular subjects developed tolerance against tyrosine supplementation. The temporary improvements experienced by these subjects, however, leaves open the potential usage of tyrosine in cases of ADD that are of a transient type.


Dosage and Safety
Most of the successful human trials with tyrosine, especially those conducted by the U.S. military, used doses of 100-150 milligrams for every kilogram of bodyweight. This would equate to 8-12 grams of tyrosine for a 175 pound subject, and no discernibly adverse side effects were noted.