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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Vitamin C [EPC]
Tyrosine is a non-essential amino acid and a precursor to key neurotransmitters like dopamine and norepinephrine. It is used clinically in parenteral nutrition and for managing conditions like phenylketonuria (PKU).
Name
Tyrosine
Raw Name
TYROSINE
Category
Vitamin C [EPC]
Drug Count
22
Variant Count
64
Last Verified
February 17, 2026
RxCUI
800401, 800405, 800416, 800420, 800434, 800438, 800440, 800444, 801644, 801648, 800341, 800345, 800998, 801000, 801010, 801012, 801019, 801021, 801029, 801031, 1090635, 1090639, 831426, 831430, 800584, 800588, 801133, 801136, 1601982, 800611, 1189640, 801395, 801398, 801403, 801405
UNII
PQ6CK8PD0R, 5BWD2J7B4W, 535G2ABX9M, 1D5Q932XM6, 92QVL9080Y, 8KOG53Z5EM, 3B8D35Y7S4, 817L1N4CKP, 0U46U6E8UK, 47E5O17Y3R, 459AG36T1B, 2S58538ZG2, 29SUH5R3HU, 6CA025Y4FG, POD38AIF08, 0YPR65R21J, W61ME6Q717, 308LM01C72, 1NT28V9397, 42HK56048U, OF5P57N2ZX, 7S82P3R43Z, 94ZLA3W45F, 6SO6U10H04, K848JZ4886, Z4B6561488, 0RH81L854J, T7S323PKJS, 4QD397987E, 04Y7590D77, GMW67QNF9C, 0G389FZZ9M, K3Z4F929H6, AE28F7PNPL, E524N2IXA3, 19F5HK2737, E4GA8884NN, 6EC706HI7F, 9DLQ4CIU6V, TLM2976OFR, 452VLY9402, 451W47IQ8X, NQX9KB6PCL, L0PFEMQ1DT, 3EM4VW6TQN, 8DUH1N11BX, HG18B9YRS7, IY9XDZ35W2, 2ZD004190S, TE7660XO1C, JNJ23Q2COM, 30KYC7MIAI, 3KX376GY7L, TTL6G7LIWZ, 1EQV5MLY3D, M4I0D6VV5M, CI71S98N1Z, 4550K0SC9B, 02F3473H9O, 76Q83YLO3O, 93371T1BXP, XF417D3PSL, 5Z33R5TKO7, P47W069U38, 5HOC10FSIC, W8N8R55022, 2I1RTO1MBR, 9901V1E867, SMV71DDI4T, 7JM57I419K, 190Q9MB3U3, O3B55K4YKI, E934B3V59H, 91GQH8I5F7, 88XHZ13131, 51FI676N6F, FOF26T73HA, HF539G9L3Q, 8ID597Z82X, 40GMI0R60L, 660YQ98I10, 1K573LC5TV, J17GBZ5VGX, ETJ7Z6XBU4, 70WT22SF4B, AB6MNQ6J6L, VP2CN2G7Y8, 49NGK53TPQ, N6R0856Z79, 9Y3J3362RY, 050QZ2EDK7, 03T60V100Y, T0920P9Z9A, 3G7U72W8DA, MN18OTN73W, 91D9GV0Z28, 2ACZ6IPC6I, 808T94CEU6, 536BQ2JVC7, URK9D85MYO, 55G8SQ543S, V5741391RG, 4X4HLN92OT, LX22YL083G, SK47B8698T, YP1H63LJ2K, 241ATL177A, 2679MF687A, 2E32821G6I, 11E6VI8VEG, 1PIP394IID, 0B4FDL9I6P, 5L51B4DR1G, T90W4582DU, MA9CQJ3F7F, 1TH8Q20J0U, ET3651ZLOU, U182GP2CF3, 1MBW07J51Q, 00UK7646FG, 19FUJ2C58T, 4QQN74LH4O, 9679TC07X4, C88X29Y479, 0E53J927NA, FQ3DRG0N5K, A236A06Y32, 810258W28U, 5HW39H9KDH, M2776SWB29, S6G2NLH4Y7, 8EKI9QEE2H, G39P120JQT, 07YL55QKZ9, 993QHL78E6, ZQH6VH092Z, 4VBP01X99F, 639KR60Q1Q, HBU87MH6OY, F9S9FFU82N, 498M34P1VZ, CZD6M4PY4B, CLF5YFS11O, BQN1B9B9HA, VYH9Y9BCCP, QDL83WN8C2, 5405K23S50, 269XH13919, 0HK2GZK66E, 25X51I8RD4, 6RV024OAUQ, DA8G610ZO5, ZT934N0X4W
About Tyrosine
Tyrosine is a non-essential amino acid and a precursor to key neurotransmitters like dopamine and norepinephrine. It is used clinically in parenteral nutrition and for managing conditions like phenylketonuria (PKU).
Detailed information about Tyrosine
This page is for informational purposes only and does not replace medical advice. Consult a qualified healthcare professional before using any medication containing Tyrosine.
From a pharmacological perspective, Tyrosine serves as the fundamental building block for several critical catecholamines, including dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline). It is also the primary precursor for thyroid hormones (triiodothyronine [T3] and thyroxine [T4]) and the pigment melanin. Because of its role in neurotransmitter synthesis, healthcare providers often examine Tyrosine's impact on cognitive function, mood regulation, and the physiological response to acute environmental stress.
Historically, Tyrosine was first isolated from the protein casein (found in cheese) by the German chemist Justus von Liebig in 1846. Since then, its role in human metabolism has been extensively mapped. In modern clinical practice, Tyrosine is most commonly administered as part of total parenteral nutrition (TPN) for patients who cannot receive oral or enteral feeds, or as a specialized medical food for patients with inherited metabolic disorders. While it is widely available as a dietary supplement, its clinical use in high-dose therapeutic settings requires careful medical supervision to avoid disruptions in neurotransmitter balance or interactions with dopaminergic medications.
The mechanism of action for Tyrosine is rooted in its role as a substrate for enzymatic conversion. Once ingested or infused, Tyrosine is transported across the blood-brain barrier via the large neutral amino acid (LNAA) transporter system. Inside the central nervous system and the adrenal medulla, the enzyme tyrosine hydroxylase acts as the rate-limiting step, converting L-tyrosine into L-DOPA (L-3,4-dihydroxyphenylalanine). L-DOPA is then rapidly decarboxylated into dopamine. Depending on the cell type, dopamine may be further converted into norepinephrine and epinephrine.
Under normal physiological conditions, tyrosine hydroxylase is saturated, meaning additional Tyrosine intake does not necessarily increase neurotransmitter levels. However, during periods of high stress—such as extreme cold, sleep deprivation, or intense cognitive demand—neurotransmitter turnover increases significantly. In these specific 'depleted' states, supplemental Tyrosine may help maintain catecholamine levels, thereby preventing the cognitive decline typically associated with acute stress. This is often referred to as the 'Catecholamine Hypothesis' of Tyrosine action.
Furthermore, in the thyroid gland, Tyrosine residues within the protein thyroglobulin are iodinated to produce thyroid hormones. This makes Tyrosine essential for maintaining metabolic rate and thermogenesis. In the skin, Tyrosine is converted by the enzyme tyrosinase into melanin, providing protection against ultraviolet (UV) radiation.
Understanding the pharmacokinetics of Tyrosine is essential for determining appropriate dosing intervals and predicting potential interactions.
Tyrosine is utilized in several FDA-approved and clinically recognized capacities:
Tyrosine is available in various formulations to suit different clinical needs:
> Important: Only your healthcare provider can determine if Tyrosine is right for your specific condition. Improper use can lead to significant metabolic imbalances.
Dosage for Tyrosine varies significantly based on the underlying condition being treated and the patient's nutritional status.
Tyrosine is critical in pediatric populations, especially neonates and infants with metabolic disorders.
Patients with chronic kidney disease (CKD) may have altered amino acid metabolism. While Tyrosine itself is not typically nephrotoxic, the nitrogen load from high-dose amino acids can exacerbate uremia. Healthcare providers may reduce the total protein/amino acid intake in patients with a GFR below 30 mL/min.
In cases of severe liver failure or cirrhosis, the liver's ability to metabolize aromatic amino acids (including Tyrosine and Phenylalanine) is diminished. This can lead to an imbalance in the plasma amino acid profile, potentially contributing to hepatic encephalopathy. Dosing must be carefully monitored via plasma amino acid chromatography.
Older adults may have decreased renal clearance and a higher prevalence of cardiovascular conditions. Dosing should generally start at the lower end of the spectrum to monitor for effects on blood pressure and heart rate.
If you miss a dose of Tyrosine, take it as soon as you remember. However, if it is nearly time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not double the dose to catch up, as this can increase the risk of gastrointestinal distress or hypertensive effects.
Signs of a Tyrosine overdose may include severe nausea, vomiting, diarrhea, intense headache, rapid heartbeat (tachycardia), and a significant increase in blood pressure. In extreme cases, over-supplementation could potentially lead to a 'serotonin-norepinephrine imbalance.' If an overdose is suspected, contact a Poison Control Center or seek emergency medical attention immediately.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking Tyrosine without medical guidance, especially if you are using it to manage a metabolic disorder.
Most individuals tolerate Tyrosine well at standard nutritional doses. However, when used at higher therapeutic levels, the following common side effects may occur:
> Warning: Stop taking Tyrosine and call your doctor immediately if you experience any of the following serious symptoms:
Data on the continuous, long-term use of high-dose Tyrosine (beyond several months) is limited. Potential concerns include:
There are currently no FDA black box warnings for L-Tyrosine. However, it is important to note that Tyrosine is often sold as a dietary supplement, which does not undergo the same rigorous pre-market safety testing as prescription drugs. For prescription amino acid injections containing Tyrosine, warnings focus on the risks of aluminum toxicity in neonates and the potential for fluid/electrolyte imbalances.
Report any unusual symptoms to your healthcare provider. Monitoring of blood pressure and heart rate is recommended when starting high-dose therapy.
Tyrosine is a potent metabolic precursor and should not be viewed as an inert substance. Its ability to cross the blood-brain barrier and influence the synthesis of hormones and neurotransmitters means it can significantly alter physiological states. Patients with a history of psychiatric disorders, cardiovascular disease, or endocrine imbalances must exercise extreme caution.
No FDA black box warnings for Tyrosine. However, healthcare providers should be aware that parenteral amino acid solutions containing Tyrosine may carry warnings regarding Aluminum Toxicity, particularly in premature infants with impaired renal function.
If you are taking Tyrosine under medical supervision for a specific condition, your doctor may require the following tests:
In most individuals, Tyrosine does not cause impairment. However, because it can cause jitteriness, anxiety, or a sudden 'crash' in some people, you should observe how Tyrosine affects you before driving or operating heavy machinery.
There is no direct chemical interaction between Tyrosine and alcohol. However, alcohol is a central nervous system depressant, while Tyrosine can be stimulatory. Mixing the two may mask the effects of alcohol, leading to impaired judgment, or may exacerbate the gastrointestinal side effects of Tyrosine.
Tyrosine does not typically cause a physical withdrawal syndrome. However, if you have been taking high doses for cognitive support, you may experience a temporary return of fatigue or 'brain fog' upon discontinuation. It is generally best to taper the dose over several days rather than stopping abruptly.
> Important: Discuss all your medical conditions, especially thyroid disorders and psychiatric history, with your healthcare provider before starting Tyrosine.
MAO Inhibitors (MAOIs): This is the most critical interaction. Monoamine oxidase is the enzyme responsible for breaking down catecholamines (like norepinephrine). Tyrosine increases the production of these catecholamines. Taking them together can lead to a dangerous, rapid accumulation of norepinephrine, resulting in a hypertensive crisis (a sudden, life-threatening spike in blood pressure). Examples include phenelzine (Nardil), tranylcypromine (Parnate), and selegiline (Emsam).
For each major interaction, the management strategy usually involves separating doses by several hours or avoiding the combination entirely.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, including over-the-counter vitamins.
Tyrosine must NEVER be used in the following circumstances:
Conditions requiring a careful risk-benefit analysis by a physician include:
There is no known cross-sensitivity between Tyrosine and common drug classes like penicillins or sulfonamides. However, individuals with a known allergy to any component of a specific Tyrosine formulation (such as fillers like magnesium stearate or gelatin in capsules) should avoid those specific products.
> Important: Your healthcare provider will evaluate your complete medical history, including genetic testing if necessary, before prescribing Tyrosine or recommending high-dose supplementation.
There is insufficient clinical data regarding the safety of high-dose Tyrosine supplementation during pregnancy. While Tyrosine is a natural amino acid found in food, the metabolic demands of pregnancy are complex. High levels of Tyrosine in the maternal blood could theoretically affect fetal neurotransmitter development. Most healthcare providers recommend obtaining Tyrosine only through a standard diet during pregnancy unless supplementation is required to manage a specific condition like PKU. In PKU patients, maintaining stable Tyrosine levels is actually crucial for a healthy pregnancy, but this must be managed by a metabolic specialist.
Tyrosine is a natural component of breast milk. However, it is unknown how supplemental high-dose Tyrosine affects the concentration in milk or the nursing infant. Because the infant's blood-brain barrier and metabolic pathways are still developing, high-dose supplementation by the mother is generally discouraged unless medically necessary.
Tyrosine is safely used in children as part of infant formulas and parenteral nutrition. It is also essential for children with PKU. However, it is not approved for use as a cognitive enhancer or for ADHD in children. There is concern that altering neurotransmitter precursors in a developing brain could have long-term developmental consequences. Any use in children must be under the direct supervision of a pediatrician.
Older adults are more likely to have underlying hypertension, cardiovascular disease, and renal impairment. They are also more likely to be taking multiple medications (polypharmacy). In the elderly, Tyrosine should be used with extreme caution due to the increased risk of blood pressure spikes and potential interactions with Parkinson's or thyroid medications. Lower starting doses and frequent monitoring are recommended.
In patients with a GFR < 60 mL/min, the clearance of amino acid metabolites may be reduced. While Tyrosine is not directly toxic to the kidneys, the resulting nitrogenous waste can be problematic. Dosing adjustments should be made based on the patient's total daily protein allowance.
In patients with Child-Pugh Class B or C hepatic impairment, the metabolism of aromatic amino acids is significantly altered. Tyrosine levels can rise to abnormal levels, contributing to the 'false neurotransmitter' theory of hepatic encephalopathy. Supplementation is generally contraindicated in patients with advanced liver disease unless specifically indicated for nutritional support.
> Important: Special populations require individualized medical assessment and should never self-supplement with Tyrosine.
Tyrosine acts as a biochemical precursor. Its primary clinical effects are mediated through its conversion into catecholamines. The pathway is as follows:
By providing an abundance of substrate, Tyrosine ensures that during periods of high neuronal firing (stress), the rate-limiting enzyme (tyrosine hydroxylase) has sufficient material to maintain neurotransmitter synthesis, thereby preventing the depletion of the 'labile pool' of catecholamines.
The onset of Tyrosine's effect on plasma levels is rapid (within 1 hour), but the cognitive effects may take 60–90 minutes to manifest as it requires time for transport and conversion. The duration of effect is relatively short, typically 2–4 hours. There is no evidence of pharmacological tolerance with short-term use, though long-term use may lead to down-regulation of receptors or enzymes.
| Parameter | Value |
|---|---|
| Bioavailability | High (Oral) |
| Protein Binding | Low (<10%) |
| Half-life | 1.5 - 3.0 hours |
| Tmax | 1 - 2 hours |
| Metabolism | Hepatic (Aminotransferase pathway) |
| Excretion | Renal (Primary) |
Tyrosine is categorized as a Non-essential Amino Acid. In clinical databases, it is found under Amino Acids [EPC] and Nutritional Agents. It is related to other neurotransmitter precursors like L-Tryptophan and L-Phenylalanine.
Medications containing this ingredient
Common questions about Tyrosine
Tyrosine is primarily used as a nutritional supplement to support the production of neurotransmitters like dopamine and norepinephrine, which are essential for mood and cognitive function. Clinically, it is a vital component of parenteral nutrition for patients who cannot eat and is a mandatory supplement for individuals with phenylketonuria (PKU). Some evidence suggests it may help improve mental performance and alertness during periods of physical stress, such as cold exposure or sleep deprivation. It is also used by the body to produce thyroid hormones and melanin, the pigment responsible for skin and hair color. However, it should only be used for these purposes under the guidance of a healthcare professional.
The most common side effects of Tyrosine include gastrointestinal issues such as nausea, heartburn, and upper abdominal pain. Some users also report experiencing headaches, particularly tension-type headaches, and a feeling of restlessness or 'jitters' similar to a caffeine rush. These effects are usually mild and occur more frequently when taking high doses on an empty stomach. Because Tyrosine can be stimulatory, it may also cause insomnia if taken too close to bedtime. Most of these side effects resolve on their own as the body adjusts to the supplement or if the dosage is reduced.
While there is no known direct dangerous chemical reaction between Tyrosine and alcohol, it is generally not recommended to mix them. Alcohol acts as a central nervous system depressant, whereas Tyrosine can have stimulatory effects by increasing norepinephrine levels. This combination can lead to unpredictable changes in mood and alertness, potentially masking the intoxicating effects of alcohol and leading to impaired judgment. Additionally, both substances can irritate the gastrointestinal tract, increasing the risk of nausea or heartburn. Always consult your doctor about your alcohol consumption while taking any metabolic supplement.
The safety of high-dose Tyrosine supplementation during pregnancy has not been well-established through clinical trials. While it is a naturally occurring amino acid found in many foods, taking it in concentrated supplement form could potentially alter the delicate balance of neurotransmitters in the developing fetus. For women with phenylketonuria (PKU), Tyrosine supplementation is often necessary but must be strictly managed by a specialist. For most other women, it is recommended to avoid Tyrosine supplements and focus on a balanced diet rich in natural protein sources. Always discuss any supplements with your obstetrician before use.
The time it takes for Tyrosine to work depends on the desired effect. For cognitive support during acute stress, plasma levels typically peak within 1 to 2 hours after oral ingestion, and clinical effects are usually observed within 60 to 90 minutes. However, for conditions like managing thyroid function or nutritional deficiencies, it may take several days or even weeks of consistent use to notice any physiological changes. Because its half-life is relatively short (about 2 hours), its effects do not last long in the body, which is why it is often taken in multiple doses throughout the day when used for therapeutic purposes.
In most cases, Tyrosine can be stopped suddenly without experiencing dangerous withdrawal symptoms, as it is a naturally occurring amino acid. However, if you have been taking high doses for a long period to support mood or cognitive function, you might experience a temporary 'rebound' effect characterized by fatigue, lethargy, or decreased mental clarity. This happens as the brain readjusts its neurotransmitter synthesis pathways. To avoid this, it is often recommended to gradually taper your dose over a few days. If you are using Tyrosine to manage a medical condition like PKU, you must never stop taking it without direct instructions from your doctor.
If you miss a dose of Tyrosine, you should take it as soon as you remember, provided it is not almost time for your next scheduled dose. If the next dose is only a few hours away, it is better to skip the missed dose and continue with your regular schedule. You should never take two doses at the same time to make up for a missed one, as this increases the risk of side effects like nausea, palpitations, or a spike in blood pressure. Maintaining a consistent schedule is the best way to ensure the supplement's effectiveness, especially when used for metabolic support.
There is no clinical evidence to suggest that Tyrosine causes weight gain; in fact, the opposite may be true in some cases. Because Tyrosine is a precursor to thyroid hormones (which regulate metabolism) and catecholamines (which can suppress appetite and increase energy expenditure), it is sometimes studied for its role in weight management. However, it is not an FDA-approved weight loss drug. Any changes in weight while taking Tyrosine should be monitored, as they could also indicate an underlying change in thyroid function. If you notice significant or unexplained weight changes, you should contact your healthcare provider for an evaluation.
Tyrosine has several significant drug interactions that must be considered. It should never be taken with MAO inhibitors due to the risk of a hypertensive crisis. It can also interfere with the absorption of Levodopa, a common medication for Parkinson's disease, and may interact with thyroid medications or stimulants like Adderall. Because Tyrosine competes with other amino acids for transport into the brain, taking it with high-protein foods or other amino acid supplements like Tryptophan can reduce its effectiveness. Always provide your doctor with a full list of your current medications and supplements before starting Tyrosine.
Yes, Tyrosine is widely available as a generic dietary supplement under the name L-Tyrosine. It is sold by numerous manufacturers in various forms, including capsules, tablets, and bulk powder. In the clinical setting, Tyrosine is also available as a component of generic amino acid injections used for parenteral nutrition. Because it is a naturally occurring substance, it cannot be patented in its basic form, which keeps the cost relatively low compared to prescription pharmaceuticals. However, the quality and purity of generic supplements can vary, so it is best to choose products that have been third-party tested.