|Summary sheet: Tyrosine|
|Common names||Tyrosine, L-Tyrosine, 4-Hydroxyphenylalanine|
|Psychoactive class||Stimulant (Weak)|
|Chemical class||Phenethylamine / Amino acid|
|Routes of Administration|
Tyrosine (also known as L-Tyrosine and 4-hydroxyphenylalanine) is a non-essential amino acid that serves a precursor to dopamine, adrenaline and norepinephrine in the human body. As a supplement, it is reported to act as a mild stimulant. It is also one of the 22 amino acids that are used by cells to synthesize proteins and is abundant in many high-protein foods, such as chicken, turkey, fish, cottage cheese, cheese, yogurt, almonds, milk, avocados, bananas, peanuts, pumpkin seeds, sesame seeds and soy products.
Some evidence suggests tyrosine supplementation can affect performance on working memory tasks under certain conditions, especially stress. Tyrosine may enhance convergent (double-task) thinking. In one study, tyrosine even seemed to reverse some of the detrimental effects of sleep deprivation on cognitive performance. However, if tyrosine increases working memory performance by elevating catecholamine levels, the effect could easily be short-lived. Some animal studies have shown dopamine levels quickly return to baseline.
Tyrosine is a non-essential phenylalanine-derived amino acid. Tyrosine's structure comprises a para-hydroxylated phenyl ring connected to a pentanoic acid group, which is a five member carbon chain with a carboxyl (C(=O)OH) group on the terminal carbon. This pentanoic acid chain is substituted at R2 with an amino group in levorotary orientation.
Three structural isomers of L-tyrosine are known. In addition to the common amino acid L-tyrosine, which is the para isomer (para-tyr, p-tyr or 4-hydroxyphenylalanine), there are two additional regioisomers, namely meta-tyrosine (also known as 3-hydroxyphenylalanine, L-m-tyrosine, and m-tyr) and ortho-tyrosine (o-tyr or 2-hydroxyphenylalanine), that occur in nature. The m-tyr and o-tyr isomers, which are rare, arise through non-enzymatic free-radical hydroxylation of phenylalanine under conditions of oxidative stress.
In plants and most microorganisms, tyr is produced via prephenate, an intermediate on the shikimate pathway. Prephenate is oxidatively decarboxylated with retention of the hydroxyl group to give p-hydroxyphenylpyruvate, which is transaminated using glutamate as the nitrogen source to give tyrosine and α-ketoglutarate.
Mammals synthesize tyrosine from the essential amino acid phenylalanine (phe), which is derived from food. The conversion of phe to tyr is catalyzed by the enzyme phenylalanine hydroxylase, a monooxygenase. This enzyme catalyzes the reaction causing the addition of a hydroxyl group to the end of the 6-carbon aromatic ring of phenylalanine, such that it becomes tyrosine.
The effects of tyrosine as a supplement or psychoactive compound are due to it being a precursor to catecholamine neurotransmitters. Supplemental L-Tyrosine is converted by the body into L-DOPA which is then decarboxylated into dopamine, which later turns into norepinephrine and is then finally converted to epinephrine. This means it effectively boosts the levels of these neurotransmitters in the brain, resulting in stimulating and euphoric effects. These three neurotransmitters are collectively referred to as "catecholamines."
The process of catecholamine synthesis within the body is limited to a localized substrate pool, meaning that the subjective effects of tyrosine can often reach an "upper-limit" at heavy dosages in which additional supplementation for the purposes of intensify one's stimulation becomes ineffective.
Aside from being a proteinogenic amino acid, tyrosine has a special role by virtue of the phenol functionality. It occurs in proteins that are part of signal transduction processes and functions as a receiver of phosphate groups that are transferred by way of protein kinases. Phosphorylation of the hydroxyl group can change the activity of the target protein, or may form part of a signaling cascade via SH2 domain binding.
In comparison to traditional stimulants such as amphetamine and methylphenidate, tyrosine can be described as more "natural" feeling, less jittery, and with fewer side effects and a milder come down or "crash." It is significantly less forced, with no distinct body high. It is also less euphoric and recreational but more functional.
Disclaimer: The effects listed below cite the Subjective Effect Index (SEI), an open research literature based on anecdotal user reports and the personal analyses of PsychonautWiki contributors. As a result, they should be viewed with a healthy degree of skepticism.
It is also worth noting that these effects will not necessarily occur in a predictable or reliable manner, although higher doses are more liable to induce the full spectrum of effects. Likewise, adverse effects become increasingly likely with higher doses and may include addiction, severe injury, or death ☠.
- The effects which occur during the offset of a stimulant experience generally feel negative and uncomfortable in comparison to the effects which occurred during its peak. This is often referred to as a "comedown" and occurs because of neurotransmitter depletion. It is significantly less intensive and uncomfortable with tyrosine in comparison to other more traditional stimulants such as amphetamine or methylphenidate, but it still exists and its effects commonly include:
- Anxiety suppression
- Analysis enhancement
- Cognitive euphoria - Tyrosine can cause mild euphoria at strong doses
- Creativity enhancement
- Focus enhancement
- Increased libido
- Increased music appreciation
- Memory enhancement
- Thought acceleration
- Motivation enhancement
- Stamina enhancement
There are currently no anecdotal reports which describe the effects of this compound within our experience index. Additional experience reports can be found here:
Toxicity and harm potential
Tyrosine is physically safe, is not known to cause brain damage, and has an extremely low toxicity relative to dose. Similar to many other nootropic drugs, there are relatively few physical side effects associated with acute tyrosine exposure. Various studies have shown that in reasonable doses in a careful context, it presents no negative cognitive, psychiatric or toxic physical consequences of any sort. However, it is still strongly recommended that one use harm reduction practices when using this drug.
Tolerance and addiction potential
Tyrosine may potentially be mildly habit forming and the desire to use it may actually increase with use. This is because of its dopaminergic properties. However, in comparison to other more traditional stimulants such as amphetamine or methylphenidate, it is not nearly as addictive or compulsive.
Tolerance to the effects of tyrosine are quickly built after repeated and frequent usage. After that, it takes about 7 days for the tolerance to be reduced to half and 14 days to be back at baseline (in the absence of further consumption). Tyrosine presents cross-tolerance with other dopaminergic stimulants, meaning that after the consumption of tyrosine, most other stimulant compounds will have a reduced effect.
Warning: Many psychoactive substances that are reasonably safe to use on their own can suddenly become dangerous and even life-threatening when combined with certain other substances. The following list provides some known dangerous interactions (although it is not guaranteed to include all of them).
Always conduct independent research (e.g. Google, DuckDuckGo, PubMed) to ensure that a combination of two or more substances is safe to consume. Some of the listed interactions have been sourced from TripSit.
- Stimulants - Tyrosine is stimulatory on its own. Therefore, it may theoretically interact with other stimulatory pharmaceuticals or supplements and cause dangerously high blood pressure or heartrate.
- 25x-NBOMe & 25x-NBOH - 25x compounds are highly stimulating and physically straining. Combinations with Tyrosine should be strictly avoided due to the risk of excessive stimulation and heart strain. This can result in increased blood pressure, vasoconstriction, panic attacks, thought loops, seizures, and heart failure in extreme cases.
- Alcohol - Combining alcohol with stimulants can be dangerous due to the risk of accidental over-intoxication. Stimulants mask alcohol's depressant effects, which is what most people use to assess their degree of intoxication. Once the stimulant wears off, the depressant effects will be left unopposed, which can result in blackouts and severe respiratory depression. If mixing, the user should strictly limit themselves to only drinking a certain amount of alcohol per hour.
- DXM - Combinations with DXM should be avoided due to its inhibiting effects on serotonin and norepinephrine reuptake. There is an increased risk of panic attacks and hypertensive crisis, or serotonin syndrome with serotonin releasers (MDMA, methylone, mephedrone, etc.). Monitor blood pressure carefully and avoid strenuous physical activity.
- MDMA - Any neurotoxic effects of MDMA are likely to be increased when other stimulants are present. There is also a risk of excessive blood pressure and heart strain (cardiotoxicity).
- MXE - Some reports suggest combinations with MXE may dangerously increase blood pressure and increase the risk of mania and psychosis.
- Dissociatives - Both classes carry a risk of delusions, mania and psychosis, and these risk may be multiplied when combined.
- Stimulants - Tyrosine may be dangerous to combine with other stimulants like cocaine as they can increase one's heart rate and blood pressure to dangerous levels.
- Tramadol - Tramadol is known to lower the seizure threshold and combinations with stimulants may further increase this risk.
- MDMA - The neurotoxic effects of MDMA may be increased when combined with amphetamine and other stimulants.
This legality section is a stub.
As such, it may contain incomplete or wrong information. You can help by expanding it.
Tyrosine is unscheduled across the world and is not known to be specifically illegal within any country.
- Foods highest in Tyrosine
- Molnár, G. A., Wagner, Z., Markó, L., Kó Szegi, T., Mohás, M., Kocsis, B., Matus, Z., Wagner, L., Tamaskó, M., Mazák, I., Laczy, B., Nagy, J., Wittmann, I. (November 2005). "Urinary ortho-tyrosine excretion in diabetes mellitus and renal failure: evidence for hydroxyl radical production". Kidney International. 68 (5): 2281–2287. doi:10.1111/j.1523-1755.2005.00687.x. ISSN 0085-2538.
- Molnár, G. A., Nemes, V., Biró, Z., Ludány, A., Wagner, Z., Wittmann, I. (January 2005). "Accumulation of the hydroxyl free radical markers meta-, ortho-tyrosine and DOPA in cataractous lenses is accompanied by a lower protein and phenylalanine content of the water-soluble phase". Free Radical Research. 39 (12): 1359–1366. doi:10.1080/10715760500307107. ISSN 1071-5762.
- Nakashima, A., Hayashi, N., Kaneko, Y. S., Mori, K., Sabban, E. L., Nagatsu, T., Ota, A. (November 2009). "Role of N-terminus of tyrosine hydroxylase in the biosynthesis of catecholamines". Journal of Neural Transmission (Vienna, Austria: 1996). 116 (11): 1355–1362. doi:10.1007/s00702-009-0227-8. ISSN 1435-1463.
- TYROSINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews
- Delawary, M., Tezuka, T., Kiyama, Y., Yokoyama, K., Inoue, T., Hattori, S., Hashimoto, R., Umemori, H., Manabe, T., Yamamoto, T., Nakazawa, T. (30 November 2010). "NMDAR2B tyrosine phosphorylation regulates anxiety-like behavior and CRF expression in the amygdala". Molecular Brain. 3 (1): 37. doi:10.1186/1756-6606-3-37. ISSN 1756-6606.
- Yilmazer-Hanke, D. M., Hantsch, M., Hanke, J., Schulz, C., Faber-Zuschratter, H., Schwegler, H. (1 January 2004). "Neonatal thyroxine treatment: changes in the number of corticotropin-releasing-factor (CRF) and neuropeptide Y (NPY) containing neurons and density of tyrosine hydroxylase positive fibers (TH) in the amygdala correlate with anxiety-related behavior of wistar rats". Neuroscience. 124 (2): 283–297. doi:10.1016/j.neuroscience.2003.12.004. ISSN 0306-4522.
- Skelton, M. R., Ponniah, S., Wang, D. Z.-M., Doetschman, T., Vorhees, C. V., Pallen, C. J. (12 September 2003). "Protein tyrosine phosphatase alpha (PTPα) knockout mice show deficits in Morris water maze learning, decreased locomotor activity, and decreases in anxiety". Brain Research. 984 (1): 1–10. doi:10.1016/S0006-8993(03)02839-7. ISSN 0006-8993.
- Colzato, L. S., Haan, A. M. de, Hommel, B. (September 2015). "Food for creativity: tyrosine promotes deep thinking". Psychological Research. 79 (5): 709–714. doi:10.1007/s00426-014-0610-4. ISSN 1430-2772.
- Thomas, J. R., Lockwood, P. A., Singh, A., Deuster, P. A. (November 1999). "Tyrosine improves working memory in a multitasking environment". Pharmacology, Biochemistry, and Behavior. 64 (3): 495–500. doi:10.1016/s0091-3057(99)00094-5. ISSN 0091-3057.
- Mahoney, C. R., Castellani, J., Kramer, F. M., Young, A., Lieberman, H. R. (23 November 2007). "Tyrosine supplementation mitigates working memory decrements during cold exposure". Physiology & Behavior. 92 (4): 575–582. doi:10.1016/j.physbeh.2007.05.003. ISSN 0031-9384.
- Talaie, H.; Panahandeh, R.; Fayaznouri, M. R.; Asadi, Z.; Abdollahi, M. (2009). "Dose-independent occurrence of seizure with tramadol". Journal of Medical Toxicology. 5 (2): 63–67. doi:10.1007/BF03161089. eISSN 1937-6995. ISSN 1556-9039. OCLC 163567183.
- Gillman, P. K. (2005). "Monoamine oxidase inhibitors, opioid analgesics and serotonin toxicity". British Journal of Anaesthesia. 95 (4): 434–441. doi: . eISSN 1471-6771. ISSN 0007-0912. OCLC 01537271. PMID 16051647.