What is L-Tyrosine?
L-tyrosine is one of the conditionally essential amino acids, used as a building block for catecholamines such as noradrenaline and dopamine. (1) Being an amino acid, it is also used to build protein, meaning that it is a precursor for muscle repair and growth potential. It is a conditionally essential amino acid because its synthesis can be limited under special pathophysiological conditions such as in severe catabolic stress.
Tyrosine is synthesized in the body from phenylalanine, an essential amino acid. (2) If phenylalanine is deficient in the diet, and tyrosine is not in daily food, then there will be a problem. Tyrosine can be obtained from casein, a milk protein and other milk-based products. It is also present in non-dairy foods including meat, red wine, pumpkin and sesame seeds, peanuts, almonds, avocados and lima beans. (3)
When supplemented, it acts as a nootropic and adaptogen which has stimulatory effects that appear to be anti-stress for acute stressors and preserve stress-induced memory deficits.
How Does L-Tyrosine Work?
As mentioned above, L-tyrosine plays a role with the neurotransmitters, and most importantly, dopamine. When ingested, it is absorbed into the bloodstream then transported into various target organs. In the brain, it is turned into a molecule known as L-DOPA (a precursor of dopamine) by the enzyme tyrosine hydroxylase. Dopamine can then be converted to other catecholamines-noradrenaline and epinephrine. (4) Thyroid hormones T3 and T4 are also derived from tyrosine.
Tyrosine is also a precursor to natural phenols, melanin (skin pigment), and alkaloids.
Tyrosine Kinases
L-tyrosine serves as a receiver of phosphate groups that are transferred by way of protein kinases, known as tyrosine kinases. (5) In simple words, a tyrosine kinase is an enzyme that can move a phosphate group from ATP to a protein (in this case tyrosine) in a cell. This phosphorylation of tyrosine and other proteins by kinases is a critical mechanism in communicating signals for regulating cellular activities such as cell division. Moreover, when phosphorylation of the amino acid is done on another protein, it leads to confrontational changes that typically activate that specific protein. (6)
L-Tyrosine Vs. N-Acetyl-L-Tyrosine
Nutritional supplements come in different forms- creatine, for example, can be obtained as creatinine monohydrate, creatinine HCL, or creatine ethyl ester among many others. Each of these forms has potential benefits over the others. When it comes to tyrosine, there is L-tyrosine and N-acetyl tyrosine, abbreviated as NAT.
NAT is the amino acid tyrosine, bonded to an acetyl group. It is more soluble than L-tyrosine, and that theoretically makes it more bioavailable than L-tyrosine, but does that make it more superior? It is assumed that better solubility means a higher measure of the amount of a specific substance in the circulation. However, studies have shown that for NAT and L-tyrosine, this is not the case.
A single dose of 100mg of L-tyrosine has been shown to elevate the levels of tyrosine for up to 7 hours. Also, a dosage of 100mg/kg of orally administered tyrosine can increase plasma tyrosine by more than 100%. (7) NAT, on the other hand, 500mg administered intravenously only causes an increase of 25% of plasma tyrosine. (8)
The reason for this huge difference is that NAT is not being converted to tyrosine. For NAT to become active in the body, the acetyl group must first be removed. Because most of it is not converted to tyrosine, it is excreted in urine. Researchers have thus concluded that the usefulness of NAT to increasing tyrosine levels is not apparent. This clearly makes L-tyrosine the superior form of supplementing tyrosine.
Why take L-tyrosine?
5.1 Improves Mood
Although athletic activities have a positive effect on mood, sometimes they can have a measurable weighing impact on performance. A negative mood from the pressure to do well, anger, frustration, and fear can have an effect on the ability to run, coordinate, concentrate and synch energy with others. Combatting these feelings with nootropics like L-tyrosine boosts one physical stamina, develops muscles and physical capabilities for the appropriate mindset for competition.
As mentioned before, L-tyrosine has a role to play in the release of dopamine. In the brain, dopamine functions as a neurotransmitter that facilitates regular movement, pleasure reward-seeking behavior, memory, cognition, focus, and attention. (9) For mood, it allows the user to feel more relaxed and attentive, increasing mental concentration on training. It basically gives a sense of well-being.
During stressful situations, L-tyrosine enhances the rate of norepinephrine production for one to respond appropriately. For its ability to influence the production of these neurotransmitters, L-tyrosine has been used to help with depression and anxiety. (10)
5.2 Provides Relief From Fatigue
The desire to give an impressive athletic performance is driven by the yearning to succeed, which can only be achieved by training and unrelenting motivation. Moreover, other than training, there are other stressors- relationships, family, and work. Overtraining coupled with these stressors can lead to early onset of fatigue, which works against performance and stunts personal potential. Research has shown that fatigue is a natural response that occurs when the body is depleted of resources and accumulates too much of unhealthy substances. Meaning that fatigue does not only affect results but also puts one at risk of many chronic illnesses.
L-tyrosine helps to boost energy levels and reduce fatigue-related memory problems that are attributed to hormonal (adrenal and thyroid) insufficiencies. (11) Adrenal glands convert tyrosine to epinephrine and norepinephrine, which in turn stimulates the sympathetic nervous system. The thyroid gland also uses tyrosine to make thyroxine, a hormone that control’s the body’s basal metabolic rate. (12)
Through these two critical actions, L-tyrosine influences important metabolic pathways that control energy balance, storage, and expenditure. It promotes gluconeogenesis and lipolysis which are added benefits for an athlete as they help to lower cholesterol and increase fat loss. When used together with phenylalanine, the effects of promoting healthy metabolism and nervous system are even better.
5.3 Increases Memory & Focus
Studies have shown that through influencing the levels of various catecholamines, L-tyrosine has considerable effects on cognitive functioning. (13) L-tyrosine counteracts offsets of working memory and information processing deficits caused by environmental influences and extreme cognitive demands. A study (14) published in the Journal of Frontiers in Behavioral Neuroscience showed that participants supplemented with L-tyrosine had better performance in doing complex tasks but not the easier jobs. For complex tasks, more control is needed and L-tyrosine targets cognitive control situations.
In another study, (15) 22 healthy adults showed they had better ability to switch between tasks and modalities of thought. These participants were able to focus better and exhibited improved cognitive flexibility. On enhancing focus, L-tyrosine has shown promising results in managing Attention Deficit/Hyperactivity Disorder (ADHD).
Even in the absence of these mental conditions, athletes benefit from L-tyrosine cognitive advantages by being able to focus, concentrate and avoid being easily distracted. Though the mind is one of the least discussed aspects of success and failure, it is one of the most powerful tools in an athlete’s arsenal.
Suggested Dosage, Synergies & Administration of L-Tyrosine
The Food and Nutrition Board of the Institute of medicine recommends 33mg/kg daily (for both men and women of ages to 19 to 50). For sports nutritional supplementation, doses from 500 to 2000mg 30 to 60 minutes before exercise have been used. (17) These doses may be taken once daily, but in the case of higher doses, one may need to split into two, separated by half an hour.
L-tyrosine works in synergy with other catecholargenics, dopamine up-regulators and stimulants like methylphenidate, L-theanine, Alpha GPC and B-vitamins. Tyrosine may interact with drugs such as thyroid medications, L-dopa, and antihypertensives. Caution should, therefore, be taken when on these medications.
Minimal side effects including nausea, headache, heartburn and joint pain may be experienced especially when on higher doses or when one starts taking the supplements. Like many other amino acids, the side effects fade away with time. Also, it is best to start with the lower doses as you move to higher doses.