Tyrosine

Tyrosine is a nutrient belonging to the non-essential amino acid class.

Tyrosine is also known as beta-(para-hydroxyphenyl) alanine, alpha amino-para-hydroxyhydrocinnamic acid and (S)-alphaamino-4-hydroxybenzenepropanoic acid. L-Tyrosine is the form generally used.

Tyrosine is vital for the production of thyroid hormones, melanin pigment, and crucial neurotransmitters such as dopamine, norepinephrine, and epinephrine.

Tyrosine deficiency can result in symptoms like mental illness, exhaustion, decreased alertness, cognitive problems, low thyroid hormone levels, and decreased skin pigmentation.

Nuts, beans, oats, wheat, lima beans, pumpkin seeds, sesame seeds, soy products, poultry, fish, almonds, avocados, bananas, dairy products, meat, eggs, and fermented foods like yoghurt and miso are all excellent sources of tyrosine.

Tyrosine is absorbed in the small intestine, transported throughout the body, and then metabolised to produce thyroid hormones and neurotransmitters. In excess, Tyrosine is metabolised in the liver and excreted through the urine.

The common side effects of Tyrosine include GI disturbances, hypoglycemia and allergic reactions.

Tyrosine is available in tablets, capsules and oral powders.

Biochemical action of Tyrosine

Tyrosine belonging to the supplement class acts in several physiological processes. It works via the conversion of Tyrosine to neurotransmitters: dopamine, and norepinephrine pathway.

Tyrosine is an amino acid that functions biochemically by binding to certain receptors and through a sequence of enzyme processes. The enzyme tyrosine hydroxylase, the rate-limiting step in dopamine production, first converts it into L-DOPA. Dopamine, a neurotransmitter important for mood, motivation, and motor control, is produced after L-DOPA. D1 and D2 receptors are only a few of the many receptors that dopamine may bind to, leading to varied physiological reactions.

Tyrosine also serves as a precursor for the stress-related hormones norepinephrine and epinephrine. Norepinephrine affects heart rate, blood pressure, and energy mobilisation via acting on adrenergic receptors, namely - and -adrenergic receptors. Adrenaline and epinephrine both exist on the same adrenergic receptors and have comparable effects.

• Neurotransmitter and hormone production: Tyrosine functions as a precursor for neurotransmitters, which determines its actions. Dopamine, noradrenaline, and adrenaline are produced when DOPA is converted. The availability of amino acids, nutrients and transporters control the way the brain functions.
• Thyroid hormones: Tyrosine has a role in the control of basal metabolic rate, oxygen utilisation, cellular metabolism, growth, and development as it is a precursor for the production of thyroid hormones.
• Antioxidant: Monophenolic amino acid L-tyrosine has antioxidant properties in studies using the enzymes 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethylbenzothiazoline6-sulfonic acid (ABTS), helps in the reduction of superoxide radicals, metal chelation, and inhibition of lipid peroxidation.

Tyrosine is available in tablets, capsules and oral powders.

• Tablets/Capsules: To be swallowed whole with water/liquid, as applicable.
• Powders, oral: Powders must be mixed thoroughly with the appropriate amount of liquid and stirred well to dissolve the powder, as applicable.

Tyrosine can be used as a supplement when the amount of Tyrosine taken from the diet is insufficient.

Taking Tyrosine supplements orally may effectively treat Tyrosine deficiency caused by specific genetic diseases or other disorders.

Tyrosine supplements may help promote stress adaption mechanisms, improve cognitive function, and treat depression or reward deficient syndrome linked to noradrenaline or dopamine depletion.

When used as a supplement, Tyrosine may help enhance insulin sensitivity and glucose utilization in individuals with diabetes.

Tyrosine supplements may support brain health and cognitive function.

Vitamins and natural supplements should not replace a balanced diet.

Tyrosine can help to support as a supplement for the following health benefits:

• Phenylketonuria: Phenylketonuria, or PKU, is a hereditary condition that causes elevated amounts of phenylalanine in the blood. Those with PKU cannot break down phenylalanine. The body uses this amino acid to produce tyrosine. People with PKU should eat medical meals that include tyrosine and very little phenylalanine to avoid tyrosine levels being too low.
• Enhanced cognition: Supplemental tyrosine helps to increase derived levels, improving cognitive function. Research that provided l-tyrosine (150 mg/kg) following sleep deprivation found that it positively affected cognitive function for three hours and decreased performance and reduced default potential.
• Depression: Due to its function as a precursor to dopamine and noradrenaline and the possibility that tyrosine depletion contributes to the cause of depression, tyrosine is an effective supplement for moderate depression.
• Attention-deficit hyperactivity disorder (ADHD): The advantages of tyrosine supplementation in ADHD have not yet been proven by investigation. ADHD patients have low levels of the amino acids phenylalanine, tyrosine, and tryptophan needed to make neurotransmitters. Tyrosine may help adults with ADHD focus, according to several reviews.
• Stress adaptation: Memory and productivity are affected by stress. Tyrosine supplementation is one method used to increase stress adaption while trying to decrease this. According to a study, tyrosine increases catecholamine release when neuronal activity is elevated under stress. Tyrosine has been shown to have good benefits in clinical investigations on stressed volunteers, increasing some elements.
• Weight loss: Based on biochemical considerations and in vivo research, tyrosine supplements have been used to help people lose weight. Tyrosine might reduce hunger and promote brown adipose tissue because it increases the production of noradrenaline. Additionally, it could boost basal metabolic rate as a precursor for thyroid hormones.
• Cold stress and heat stress: Tyrosine effects on memory in the cold (4°C) were proven in a clinical trial to exhibit greater accuracy after two hours. In two narrow studies, tyrosine prevented cold-induced memory loss and maybe improved mood and shooting. Tyrosine (100 mg/kg) was used in double-blind research to lessen the effects of hypoxia and the cold. Tyrosine (6.5 g) supplementation improved cognitive function under heat exposure, according to pilot research with Indian army troops.

Tyrosine supplementation may be administered orally.

Orally: Tyrosine supplements are available as tablets, capsules and powders that can be taken orally. IsThe the best time to take tyrosine supplements is in the morning on an empty stomach as it might enhance its absorption.

The dosage and duration of treatment should be as per the clinical judgment of the treating healthcare professional).

Vitamins and natural supplements should not replace a balanced diet

This product is not intended to diagnose, treat or prevent any disease(s).

• Tablets: 500 mg, 1000 mg
• Capsules: 500mg
• Powder, oral: 4 oz (113 mg)

Dosage Adjustment for Adult Patients

MOUTH:150 mg/kg/day of tyrosine is recommended to boost alertness after a protracted period of sleep deprivation.

According to current recommendations, tyrosine should be added at a rate of 6 grammes per 100 grammes of protein for those with PKU. However, extra-independent tyrosine supplementation is not advised since it may result in significant fluctuations in the level of tyrosine in the blood and may have unfavourable side effects.

The typical dose in clinical trials appears to be 100–150 mg/kg. Divided dosing may be beneficial as levels remain above baseline for 6–8 hours following administration.

Depression, premenstrual syndrome and chronic fatigue: 500–1000 mg before meals thrice daily.

Stress: 1500 mg/day in divided doses. • Decreased libido, Parkinson’s disease, drug detoxification and weight loss: 1–2 g/day in divided doses.

Natural stimulant: 500–1000 mg on an empty stomach first thing in the morning.

Alertness following sleep deprivation: 150 mg/kg/day.

Tyrosine is available in tablets, capsules and oral powders.

Tyrosine should be used as a supplement that helps in several physiological processes and appropriate dietary restrictions.

• Avoid alcoholic beverages.
• Stay within your daily calorie needs.
• Limit foods and drinks with high Tyrosine content, like energy drinks, saturated fat, and sodium.

The dietary restriction should be individualized as per patient requirements.

Recommended Daily Allowance (RDA)

The RDA of Tyrosine has not been established as it is a non-essential amino acid that the body can synthesize from phenylalanine.

Upper Tolerable Intake (UTL):

The UTL has not been determined due to limited evidence of adverse effects from dietary intake.

Tyrosine supplementation may be contraindicated in the following conditions:

• Hypersensitivity; sensitive to Tyrosine.
• Chronic liver disease — may impair metabolism or increase biosynthesis of Tyrosine
• Malignant melanoma
• Hyperthyroidism
• Graves’ disease
• Alkaptonuria and tyrosinaemia
• Dialysis
• Kidney disease.

High-dose supplements should be used with caution in pregnancy.

High doses of l-tyrosine supplements should be cautiously used in individuals with preexisting hypertension.

Individuals who use Ecstasy should be informed that MDMA raises the amount of tyrosine in the brain, which results in long-term serotonin depletion.

Tyrosine can also cause migraine headaches. Avoid using tyrosine supplements if migraines frequently occur.

Caution is advised when consuming alcohol with Tyrosine.

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

Limit the consumption of foods and beverages higher in added sugars, saturated fat, and energy drinks, as these substances could hinder Tyrosine absorption.

The adverse reactions related to Tyrosine can be categorized as-

• Common: GI disturbances like stomach upset, nausea, or diarrhoea, especially with high doses.
• Less Common: Muscle weakness, increased appetite, rashes or skin irritation.
• Rare: Allergic reactions, hypoglycemia, seizures or convulsions.

The clinically relevant drug interactions of Tyrosine are briefly summarized here:

• Amphetamine, ephedrine, phenylpropanolamine: In rats, it has been demonstrated that l-tyrosine (200 and 400 mg/kg) increases the anorexia side effect brought on by phenylpropanolamine, ephedrine, and amphetamine in a dose-dependent way. Patients using this combination should be monitored closely. Antidepressant drugs: Combining MAOIs, tricyclic antidepressants, or selective serotonin reuptake inhibitors may theoretically result in increased blood pressure and/or improved antidepressant effects. Tyrosine may be partially converted to tyramine in the case of MAOIs, and concurrent usage of MAOIs may result in a hypertensive emergency. Unless under medical advice, tyrosine should be avoided.
• Central nervous system stimulants: As tyrosine is a precursor to many different neurotransmitters, long-term effects may occur — caution.
• Oestrogens and antiandrogen therapy: Tyrosine plasma levels in transsexual patients have been reported to decrease by up to 18.3% after 4 and 12 months of treatment with oestrogen and antiandrogen treatments.
• Levodopa: Tyrosine and l-dopa compete for absorption; as a result, concurrent administration of either chemical may result in decreased uptake of both, lowering their effectiveness.
• Morphine sulfate: Although l-tyrosine alone has little or no antinociceptive effect, it potentiates morphine-induced analgesia by 154% and considerably potentiates the antinociceptive activity of morphine in mice at 200 mg/kg. Maintain a close watch on patients who are taking tyrosine and morphine sulphate at the same time since there may be a positive interaction.
• Thyroid hormone medication: Tyrosine is a precursor to thyroid hormones, thus, it's likely that taking it together with a thyroid hormone supplement will have additive effects.

The common side of Tyrosine includes the following:

• Nausea
• Diarrhoea
• Headaches
• Abdominal pain.
• Vomiting
• Heartburn
• Fatigue

Tyrosine should be prudent in the following group of special populations.

• Pregnancy:

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

• Paediatrics:

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

Dosage Adjustment for Paediatric Patients

There are no specific dosage adjustments provided.

• Geriatrics:

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

• Lactating mothers:

There is no sufficient scientific evidence traceable regarding the use and safety of Tyrosine for use in special populations.

Dosage Adjustment in Kidney Impairment

There are no specific dosage adjustments provided.

Dosage Adjustment in Hepatic Impairment

There are no specific dosage adjustments provided.

The physician should be vigilant about the knowledge pertaining to identifying and treating overdosage of Tyrosine. Overconsumption of Tyrosine may lead to health concerns such as gastrointestinal distress, hypoglycaemia and allergic reactions.

There is no specific antidote or treatment for excessive intake of supplemental tyrosine. Tyrosine supplements should be terminated immediately when an overdose is suspected or experience any unusual symptoms after Tyrosine supplement use or dietary intake. Induce vomit, gastric lavage, or activated charcoal may also be used if ingestion is recent but only under the supervision of a medical professional. Supportive therapy should also be given, addressing any symptoms that persist or worsen. Physical treatment might be added if necessary.

Biochemistry profile of Tyrosine

Tyrosine is an amino acid made comprised of a benzene ring, a hydroxyl group, and an amino group. Its unique structure makes it essential for producing neurotransmitters, hormones, and proteins. It functions as a precursor for crucial chemicals, including neurotransmitters and hormones. Phenylalanine hydroxylase turns phenylalanine into tyrosine through a variety of enzymatic processes. The body's essential structural elements are then formed through tyrosine's involvement in protein synthesis. Additionally, catecholamines like dopamine, norepinephrine, and epinephrine, which control mood, stress response, and cardiovascular functions, are precursors to tyrosine. Tyrosine is converted into the thyroid hormones thyroxine (T4) and triiodothyronine (T3), essential for controlling metabolism.

The function of tyrosine is not limited to biosynthesis. Tyrosine kinases add phosphate groups to proteins and are essential components of cell signalling pathways that regulate cellular differentiation, growth, and communication. Proteins' functions can change when tyrosine residues are phosphorylated.

Kinetic profile:

• Absorption: Active transport pathways enable tyrosine to be absorbed from the small intestine.
• Distribution: Tyrosine is an amino acid taken into the body and then circulates via the bloodstream to different tissues, including the brain, liver, and muscle.
• Metabolism: Tyrosine goes through several metabolic processes. The brain and adrenal glands may change it into dopamine, norepinephrine, and epinephrine. In the thyroid gland, it can also be converted into thyroid hormones.
• Elimination: Tyrosine and its metabolites are mostly excreted from the body through the urine. Tyrosine that isn't used is catabolized in the liver and subsequently eliminated.

1. Braun L, Cohen M. October 1, 2014.Herbs and Natural Supplements; 4th Edition Vol-2. Australia. Elsevier.

2. National Institute of Nutrition. 2011. Dietary guidelines for Indians; 2nd Edition. Hyderabad. India

3. Tessari P. 2019. Nonessential amino acid usage for protein replenishment in humans: a method of estimation; American Society for Nutrition. Department of Medicine, University of Padova, Padova, Italy.