Generic Name: L-Tyrosine
Brand Names: L-Tyrosine
Available Dosage Forms: Oral tablet, capsule, IV, and topical
What is L-Tyrosine?
Tyrosine is a precursor to the synthesis of a multitude of neurotransmitters and has an essential role in dopamine biosynthesis.1 It is hypothesized that since Tyrosine affects neurophysiology by enhancing the release of mood manipulating neurotransmitters, it may have involvement in the management of psychotropic disorders such as depression. In a study, depletion of Tyrosine was consistently interlinked with mood disturbances in young women following psychological trauma after an unfortunate event.2
Researchers presumed that tyrosine administration upregulates the production of both dopamine and norepinephrine from brain neurons and subsequently inculcates improvement in:
-Age-related memory problems
-Age-related cognitive impairment
-Motor symptoms in Parkinson’s
-Response inhibition in young adults.
Acute administration of Tyrosine in healthy older (age 61-72) group during a clinical trial lead to a significant decline of response inhibition. However, the detrimental effects were only apparent neurally, while no changes were noticed behaviorally. The results exhibited that neurally noticeable decline in response inhibition was consistent in older adults as old age adversely affected the mode of action of Tyrosine.1 Pharmacological intervention has introduced an advanced mode of drug administration that utilizes nanoparticle technology. Use of Tyrosine nanoparticles in depressed patients has shown therapeutic efficacy similar to antidepressant agents, Fluoxetine and Desmethylimipramine.3
The negative effects of Tyrosine witnessed in older adults are dose-dependent. High doses potentiate the risk of detrimental effects in the absence of neuronal sensitivity. Increased neuronal sensitivity to Tyrosine is observed solely in demanding tasks and acute stress. Therefore, a relatively higher dose is only suitable for high neuronal firing recorded during stressful situations.1
How to use L-Tyrosine?
-Do not use more than the recommended dose on the label
-Most frequently prescribed daily dosage is 150 mg
-Total dosage is split into three dosages throughout the day
-You should take the supplement at least half an hour before having food
-L-Tyrosine is not yet approved by the FDA
-You should not use L-Tyrosine without approval from a qualified health care professional
What are the side effects of L-Tyrosine?
Who should not use L-Tyrosine?
-Those with migraine
-Those with Thyroid disorders such as Grave’s disease and hyperthyroidism
-Those taking exogenous thyroid hormone
-Those taking MAOIs and levodopa
- Bloemendaal M, Froböse MI, Wegman J, et al. Neuro-Cognitive Effects of Acute Tyrosine Administration on Reactive and Proactive Response Inhibition in Healthy Older Adults.eNeuro. 2018;5(2):ENEURO.0035-17.2018. Published 2018 Apr 30. doi:10.1523/ENEURO.0035-17.2018
- Leyton M, Young SN, Pihl RO, et al. Effects on mood of acute phenylalanine/tyrosine depletion in healthy women. Neuropsychopharmacology. 2000;22(1):52-63. doi:10.1016/S0893-133X(99)00086-X
- Alabsi A, Khoudary AC, Abdelwahed W. The Antidepressant Effect of L-Tyrosine-Loaded Nanoparticles: Behavioral Aspects [published correction appears in Ann Neurosci. 2019 Jan;25(3):141-151]. Ann Neurosci. 2016;23(2):89-99. doi:10.1159/000443575