Vegetarian TyrosineTM
90 Capsules $38.98

Tyrosine is a natural amino acid which is needed for the “synthesis of proteins, catecholamines, melanin pigment, and thyroid hormones. Tyrosine also provides energy when catabolized through parahydroxyphenyl pyruvate to fumarate and acetoacetate” [1]. Tyrosine is used to make critical hormones by both the thyroid and adrenal glands [2], thus helps the body deal with stress. Tyrosine is incorporadoted into all proteins [3]. While most tyrosine-containing supplements only contain isolated L-tyrosine, Vegetarian Tyrosine also contains all the supporting amino acids naturally found in winged beans (Psophocarpus tetragonolobus). Vegetarian Tyrosine contains no animal derivatives and is strictly vegetarian as it is a 100% bean and fermented plant extract supplied in a vegetarian capsule.

Tyrosine may reduce the net rate of protein breakdown in the body and appears to help with endurance [4]. Tyrosine has an effect on nerve impulse transmission and may “improve vigilance and lessen anxiety” [5]. Gary Null (Ph.D.) considers tyrosine to be a therapeutic amino acid for depression as well was an antiencephalopathic, antiparkinsonian, and antidepressant [6]. Women on oral contraceptives have been found to have less plasma and brain levels of tyrosine which results in a reduction in catecholamines, which affect mood. [7]. Oral consumption of tyrosine has, in some case, been shown to completely alleviate depression while increasing plasma tyrosine levels [8,9]. It has also been shown to help when MAO inhibitors did not [9]. In rat models vitamin C has enhanced the ability of tyrosine to decrease blood pressure [10,11]. Interestingly, “Tyrosine has been known to normalize blood pressure whether high or low. Tyrosine is being tested by the Air Force to enhance performance under stress” [12].

The body naturally produces tyrosine by converting it from phenylalanine [11]. “Compared with tyrosine which has a de novo synthesis component limited by phenylalanine oxidation, most nonessential amino acids have a very large de novo synthesis components because of the metabolic pathways they are involved in” [11]. This might explain why taking separate tyrosine is more helpful for many than taking other separate amino acids classified as nonessential—they can be made with much easier (with less restriction) than tyrosine can (tyrosine requires liver hydroxylation).

Vegetraian Tyrosine Supports the Adrenal Glands. Tyrosine “produces the neurotransmitter molecules dopamine, norepinephrine, and epinephrine” [16]. Epinephrine and norepinephrine are both involved in stress response. A Parkinson’s study found “l-tyrosine administration significantly increased cerebrospinal fluid (CSF) tyrosine levels in both groups of patients and significantly increased homovanillic acid levels in the group of patients pretreated with probenecid. These data suggest that l-tyrosine administration can increase dopamine turnover in patients with disorders in which physicians want to enhance dopaminergic neurotransmission” [16]. Oral tyrosine feeding has been found to significantly decrease both free and conjugated plasma norepinephrine concentrations, thus appears to be helpful for people with conditions associated with excessive sympathetic nervous system activity, including hypertension [18]. This may also explain why tyrosine helps many with anxiety. Interestingly, supplemental tyrosine appears to increase norepinephrine when it is low [9] and increase it when it is too high [18]. Adrenal gland support may be one of the reasons that there are reports of increased energy and endurance from those taking tyrosine [4,6].

Vegetarian Tyrosine Supports the Thyroid Gland. Hypothyroidism can be associated with low levels of tyrosine [19]. This is totally logical as the primary thyroid hormone (T1) is called monoiodotyrosine (iodine and tyrosine) [2]. The body converts this primary hormone from T1 to T2 (diiodotyrosine) to T3 to T4 and back to T3—but it all starts with tyrosine attaching to iodine [2]. Some naturopaths have reported success using L-tyrosine to help nutritionally support the thyroid gland [6,20]. Symptoms associated with hypothyroidism include poor metabolism, fatigue, weight problems, depression, mood swings, mental or physical slowness, temperature intolerance, dry skin, menstrual complaints, and low libido [20,21]; most with hypothyroidism do not show all the symptoms associated with it [22].

Restricting Tyrosine is Harmful for Most. Recent human research has found those with less tyrosine “became less content and more apathetic ” and “demonstrated a sad latency bias ”, thus otherwise normal people deprived of tyrosine seem to show symptoms “characteristic of clinical depression” [22]. Another human study found that by restricting phenylalanine and tyrosine, “All patients experienced problems and side-effects and increases in anxiety and depression” [23]. Another stated, “All six subjects had low or deficient blood concentrations of both tyrosine and tryptophan, which are precursors for dopamine and serotonin” yet when neutral amino acids were added, “At the end of the study all patients reported increased energy and overall improvement in well-being” [24]. An all female study found that mood and energy worsened when tyrosine and its precursor were highly restricted [25].

Some inherited conditions can interfere with tyrosine [1,11,21]. Yet for some other inherited disorders (such as children with phenylketonuria), the consumption of tyrosine is essential [1,11] (though some suggest getting it less concentrated may be a preferred method [3]). Note: People on MAO inhibitors (a family of now generally lessor used antidepressant medications as well as Deprenyl) or with conditions such as tyrosinemia [11,21] or otherwise contradicted should not take Vegetarian Tyrosine.

Vegetarian Tyrosine naturally contains carbohydrates, lipids, proteins (including essential amino acids), as found in Winged Beans Psophocarpus tetragonolobus--all the nutrients shown above are contained in beans or a fermented bean extract. Unlike many so-called “natural” formulas, Bean Tyrosine is only comprised of foods and contains no synthetic USP nutrients or isolated mineral salts, but only contains foods and food extracts.

Numerous university studies have concluded that supplements containing food nutrients are better than USP isolates. Food nutrients are better because they contain important enzymes, peptides, and phytonutrients CRITICAL to the UTILIZATION of vitamins and minerals which are not present in isolated USP nutrients. Published research has concluded that food vitamins are superior synthetic/USP vitamins.

Suggested use: 1-6 capsules per day or as recommended by your health care professional. Adjust usage according to nutritional lifestyle requirements.

Vegetarian Tyrosin Video


[1] Elsas LJ, Acosta PB. Nutrition support of inherited metabolic disease. In Modern Nutrition in Health and Disease, 8th ed. Lea & Febiger, Phil.; 1994:147-1206

[2] Guyton AC, Hall JE. Textbook of Medical Physiology, 9 th ed. W.B. Saunders, Phil, 1996

[3] van Spronsen FJ, Smit PGA, Koch R. Phenylketonuria: Tyrosine Beyond the Phenylalanine-Restricted Diet. J Inherit Metab Dis, 2001;24:1-4

[4] Blomstrand E, Newsholme EA. Effect of branch-chain amino acid supplementation on exercise-induced change in aromatic amino acid concentration in human muscle. ACTA Physiol Scand,1992;146:293-298

[5] Specific nutrients aid in high-performance activity. Nutr Week, June 4, 1994:7

[6] Null G. The Clinician’s Handbook of Natural Healing. Kensington Books, NY, 1997

[7] Moller SE. Tryptophan and Tyrosine Availability and Oral Contraceptives. Lancet, September 1, 1979:472

[8] Gelenberg AJ, Wojcik JD, Growdon JH, et al. Tyrosine for the Treatment of Depression. Am J Psychiatry, 1980;137(5):622-623

[9] Goldberg IK. L-Tyrosine in Depression. Lancet, August 16, 1980:364.

[10] Hemila H. Vitamin C and Lowering Blood Pressure: Need For Intervention Trials. Journal of Hypertension, 1991;9(11):1076-1077

[11] Shils ME, Olson JA, Shike M, Ross AC, eds. Modern Nutrition in Health and Disease, 9 th ed. Williams & Wilkins, Balt., 1999

[12] Hamiliton K. Clinical Pearls, 1992. ITServices, Sacramento, 1991

[13] Macrae R, Robinson RK, Sadler MJ. Encyclopedia of Food Science and Nutrition, Vol. 1. Academic Press, New York, 1993

[14] Venketeswaran MA, Dias DL, Weyers UV. The winged bean: A potential protein crop. In: Advances in New Crops. Timber Press, Portland, 1990:445

[15] Winged beans, mature seeds, raw; NDB No: 16135. USDA National Nutrient Database for Standard Reference, Release 16. July 2003

[16] Wenk G. Dietary factors that influence the neural substrates of memory. In The Vulnerable Brain and Environmental Risks, Vol 1. Plenum Press, New York, 1992:67-74

[17] Growdon JH, Melamed E, Logue M, et al. Effects of Oral l-Tyrosine Administration on CSF Tyrosine and Homovanillic Acid Levels in Patients With Parkinson's Disease. Life Sci, 1982;30(10):827-832

[18] Benedict CR, Anderson GH, Sole MJ. The Influence of Oral Tyrosine and Tryptophan Feeding on Plasma Catecholamines in Man. Am J Clin Nutr, 1983;38:429-435

[19] Rivlin RS, Melman KL, Sjoerdsma A. An oral tyrosine tolerance test in thyrotoxicosis and myxedema. New Engl J Med,1965;272:1143-1148

[20] Thiel R. Nutritional interventions for the thyroid. ANMA Monitor, 2000;4(1):6-14

[21] Bondy PK, Rosenberg LE, eds. Duncan’s Diseases of Metabolism: Genetics and Metabolism, 7 th ed. W.B.Saunders, Phil., 1974

[22] McLean A, Rubinsztein JS, Robbins TW, Sahakian BJ. The effects of tyrosine depletion in normal healthy volunteers: implications for unipolar depression. Psychopharmacology (Berl). 2003 Sep 4

[23] Harvie MN, Campbell IT, Howell A, Thatcher N. Acceptability and tolerance of a low tyrosine and phenylalanine diet in patients with advanced cancer -- a pilot study. J Hum Nutr Diet. 2002; 15(3): 193-202

[24] Koch R, Moseley KD, Yano S, Nelson M Jr, Moats RA. Large neutral amino acid therapy and phenylketonuria: a promising approach to treatment. Mol Genet Metab. 2003; 79(2): 110-113

[25] Leyton M, Young SN, et al. Effects on Mood of Acute Phenylalanine/Tyrosine Depletion in Healthy Women. Neuropsychopharmacology, 2000;22(1):52-63  

Some of these studies (or citations) may not conform to peer review standards, therefore, the results are not conclusive. Professionals can, and often do, come to different conclusions when reviewing scientific data. None of these statements have been reviewed by the FDA. All products distributed by Doctors’ Research, Inc. are nutritional and are not intended for the treatment or prevention of any medical condition.

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