L-TYROSINE 500mg [Amino acids]
L-Tyrosine is a non-essential amino acid that can be converted into L-DOPA and Dopamine in our brains.
The determining factor for the production of Dopamine, Norepinephrine and Epinephrine is the amount of free L-Tyrosine in the brains. When there is an insufficient level of free L-Tyrosine present in the brains, the synthesis of Dopamine, Norepinephrine and Epinephrine strongly decreases. This can lead to apathy, less concentration, impaired memory, scant alertness and overtiredness.
The level of L-tyrosine in our body depends partly on the supply of L-tyrosine in the diet, and also relies on the conversion of L-tyrosine from the amino acid phenylalanine. Phenylalanine is an essential amino acid and is therefore only obtained through the food. An estimated 67 to 90% of Phenylalanine in food is converted into L-tyrosine.
L-tyrosine is therefore essential in case there is an insufficient supply of Phenylalanine.
Our current Western diet is very low in both Phenylalanine and L-Tyrosine, causing them to be insufficiently present in the body which can lead to a decreased synthesis of Dopamine, Norepinephrine and Adrenaline.
Instructions for use
1 capsule in the morning before brekfast and 1 capsule before 16h.
Do not exceed the recommended daily dose.
Keep out of reach of young children.
Nutritional supplements should not replace a varied and balanced diet and a healthy lifestyle.
Children, pregnant women and women who are breastfeeding, consult your pharmacist before use.
Check with simultaneous intake of medicines.
No long-term use without professional advice.
Range of usage
CompositionIngredients per 2 capsules
L-tyrosine 1000 mg, Gelatine, Anti-caking agents (Calcium carbonate, Magnesium silicate, magnesium stearate, silicon dioxide)
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McTavish SF et al. Lack of effect of tyrosine depletion on mood in recovered depressed women. Neuropsychopharmacology 30(4) (2005): 786-91. PMID 15702140.
Glaeser BS, Melamed E, Growdon JH, Wurtman RJ. Elevation of plasma tyrosine after a single oral dose of L-tyrosine. Life Sci. 1979 Jul.16;25(3):265–71. PMID 481129. 10.? a b c d (en) van Spronsen FJ, van Rijn M, Bekhof J, et al. Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets. Am J Clin Nutr 2001;73:153-157. PMID 11157309.
Agharanya JC, Alonso R, Wurtman RJ. Changes in catecholamine excretion after short-term tyrosine ingestion in normally fed human subjects. Am J Clin Nutr 1981 Jan;34(1):82-7. PMID 7192489.
Gibson CJ, Wurtman RJ. Physiological control of brain catechol synthesis by brain tyrosine concentration. Biochem Pharmacol 1977;26:1137- 1142. PMID 19023.
Wurtman RJ, Larin F, Mostafapour S, Fernstrom JD. Brain catechol synthesis: control by brain tyrosine concentration. Science 1974;185:183-184. PMID 4276197.
Fernstrom JD, Fernstrom MH. Tyrosine, phenylalanine, and catecholamine synthesis and function in the brain. J. Nutr. 2007Jun.;137(6 Suppl 1):1539S–1547S–discussion1548S. PMID 17513421.
Banderet LE, Lieberman HR. Treatment with tyrosine, a neurotransmitter precursor, reduces environmental stress in humans. Brain Res Bull 22(4) (1989): 759-62. PMID 2736402
Dollins AB, Krock LP, Storm WF, et al. L-tyrosine ameliorates some effects of lower body negative pressure stress. Physiol Behav 1995;57:223-230. PMID 7716196
Deijen JB, Orlebeke JF. Effect of tyrosine on cognitive function and blood pressure under stress. Brain Res Bull 1994;33:319-323. PMID 8293316
Neri DF, Wiegmann D, Stanny RR, et al. The effects of tyrosine on cognitive performance during extended wakefulness. Aviat Space Environ Med 1995;66:313-319. PMID 7794222
Shurtleff D, Thomas JR, Schrot J, et al. Tyrosine reverses a cold-induced working memory deficit in humans. Pharmacol Biochem Behav 47(4) (1994): 935-41. PMID 8029265
Mahoney CR, Castellani J, Kramer FM, et al. Tyrosine supplementation mitigates memory decrements during cold exposure. Physiol Behav. 2007 Nov 23;92(4):575-82. Epub 2007 May 22. PMID 17585971.
Thomas JR et al. Tyrosine improves working memory in a multitasking environment. Pharmacol Biochem Behav 64(3) (1999): 495-500. PMID 10548261.
Deijen JB, Wientjes CJ, Vullinghs HF et al. Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of a combat training course. Brain Res Bull. 1999 Jan.15;48(2):203–9. PMID 10230711 .
Gelenberg A, Wojcik JD, Gibson CJ, Wurtman RJ. Tyrosine for depression. J Psychiatr Res 1982- 1983;17:175-180. PMID 6764934.
Gelenberg AJ, Wojcik JD, Growdon JH, et al. Tyrosine for the treatment of depression. Am J Psychiatry 1980;137:622-623. PMID 7369415
Goldberg IK. L-tyrosine in depression. Lancet 1980;2:364-365. PMID 6105492.
McLean A et al. The effects of tyrosine depletion in normal healthy volunteers: implications for unipolar depression. Psychopharmacology (Berl) 171(3) (2004): 286-97. PMID 12955284.
Roiser JP et al. The subjective and cognitive effects of acute tyrosine depletion in patients recovered from depression. Neuropsychopharmacology 30(4) (2005): 775-85. PMID 15688090.
Chadwick MJ, Gregory DL, Wendling G. A double-blind amino acids, L-tryptophan and L-tyrosine, and placebo study with cocaine-dependent subjects in an inpatient chemical dependency treatment center. Am J Drug Alcohol Abuse 16(3-4) (1990): 275-86. PMID 2288326.
Galloway GP et al. A historically controlled trial of tyrosine for cocaine dependence. J Psychoactive Drugs 28(3) (1996): 305-9. PMID 8895116.
Wood DR, Reimherr FW, Wender PH. Amino acid precursors for the treatment of attention deficit disorder, residual type. Psychopharmacol Bull 1985;21:146-149. PMID 3885291.
Reimherr FW, Wender PH, Wood DR, Ward M. An open trial of L-tyrosine in the treatment of attention deficit disorder, residual type. Am J Psychiatry 1987;144:1071-1073. PMID 3300376.
McTavish SF, McPherson MH, Harmer CJ et al. Antidopaminergic effects of dietary tyrosine depletion in healthy subjects and patients with manic illness. Br J Psychiatry. 2001;179:356–60. PMID 11581118.
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