L-Tyrosine

L-Tyrosine

L-Tyrosine is an amino acid, meaning that it is responsible for the creation of proteins, the basic building blocks of life. L-Tyrosine is prevalent in foods such as dairy, eggs, meat, legumes, nuts, seeds, fish, and even some grains. As a non-essential amino acid, L-Tyrosine can be synthesized in the body in the presence of phenylalanine. When there is no phenylalanine present, or a lack of L-Tyrosine is causing performance and/or health issues, it may be time to supplement the body’s ability to create this crucial amino acid.

Benefits of L-Tyrosine

Because L-tyrosine is used by your body for several important functions and processes, supplementing with this powerful enzyme can give you the following amazing health benefits:

Improves Cognitive Function and Fights Stress

L-Tyrosine aids in mental cognition and functioning, helping keep the brain alert and active. One study assessing the effects of supplemental L-Tyrosine on “extended wakefulness” found that 150 mg/kg of L-Tyrosine was able to counter the decrease in cognitive performance that was associated with lack of sleep.^[1] In another study, researchers found that cadets who took L-Tyrosine supplements during a demanding military combat training course performed better on a memory and a tracking task than the group supplied with a carbohydrate-rich drink.^[2] These findings suggest that L-Tyrosine supplementation may reduce the effects of stress and fatigue on cognitive task performance.

Lowers High Blood Pressure

According to a study published in the Brain Research Bulletin, healthy young subjects who took L-Tyrosine supplements at a dose of 100 mg/kg experienced a significant reduction in diastolic blood pressure within 15 minutes of treatment.^[3] This blood pressure-lowering effect did not occur in subjects who took placebo, indicating that L-Tyrosine supplementation has anti-hypertensive effect.

Treats Depression and Improves Mood

Results from three high quality studies assessing the effects of L-Tyrosine supplementation on depression show that the treatment appears to alleviate depressive symptoms. According to these studies, depressed patients who took oral L-Tyrosine supplements experienced an improvement in depressive symptoms as well as overall mood after the treatment.^[4-6] Researchers found that the specific mechanism by which L-Tyrosine exerts this effect is by increasing the production of dopamine, a brain chemical that acts to promote the feeling of pleasure. These findings suggest that L-Tyrosine supplementation can also be beneficial in mood changes related to menopause.

Maintains Healthy Pregnancy

L-tyrosine deficiency in expectant mothers who suffer from maternal phenylketonuria, a rare condition caused by excessive levels of phenylalanine, might lead to birth defects such as low birth weight and heart problems. Interestingly, a study published in the American Journal of Clinical Nutrition found that L-Tyrosine supplementation during pregnancy may help support normal fetal development by regulating protein synthesis, thus, preventing birth defects.^[7]  

Improves Muscle Mass, Energy Levels and Exercise Tolerance

According to a 2007 study, dietary L-Tyrosine supplementation in patients with nemaline myopathy, a disorder that primarily affects skeletal muscles, resulted in improvement of muscle mass and strength, energy levels, and exercise tolerance without any adverse side effects.^[8]

References:

1. Neri DF, Wiegmann D, Stanny RR, Shappell SA, Mccardie A, Mckay DL. The effects of tyrosine on cognitive performance during extended wakefulness. Aviat Space Environ Med. 1995;66(4):313-9.
2. Deijen JB, Wientjes CJ, Vullinghs HF, Cloin PA, Langefeld JJ. Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course. Brain Res Bull. 1999;48(2):203-9.
3. Deijen JB, Orlebeke JF. Effect of tyrosine on cognitive function and blood pressure under stress. Brain Res Bull. 1994;33(3):319-23.
4. Gelenberg AJ, Gibson CJ. Tyrosine for the treatment of depression. Nutr Health. 1984;3(3):163-73.
5. Mouret J, Lemoine P, Minuit MP, Robelin N. [L-tyrosine cures, immediate and long term, dopamine-dependent depressions. Clinical and polygraphic studies]. C R Acad Sci III, Sci Vie. 1988;306(3):93-8.
6. Goldberg IK. L-tyrosine in depression. Lancet. 1980;2(8190):364-5.
7. Rohr FJ, Lobbregt D, Levy HL. Tyrosine supplementation in the treatment of maternal phenylketonuria. Am J Clin Nutr. 1998;67(3):473-6.
8. Ryan MM, Sy C, Rudge S, et al. Dietary L-tyrosine supplementation in nemaline myopathy. J Child Neurol. 2008;23(6):609-13.