L-theanine

What it is


L-theanine is an amino acid that is commonly found in tea leaves, particularly in green and black tea. It is believed to be responsible for the relaxing effect that many people experience after drinking a cup of tea. It was first isolated from tea leaves in 1949 by Japanese scientists and has since been extensively studied for its potential health benefits. One of the most interesting aspects of L-theanine is its ability to cross the blood-brain barrier, which means that it can directly affect the brain and nervous system. In the brain, L-theanine has been shown to increase levels of neurotransmitters like dopamine and serotonin, which are involved in mood regulation and stress reduction. This may explain why many people find that drinking tea helps them feel calm and relaxed.


In addition to its effects on the brain, L-theanine has also been shown to have other potential health benefits. For example, some studies have suggested that it may have anti-inflammatory effects and may help to support the immune system. It has also been studied for its potential to improve cognitive function and protect against age-related cognitive decline.


L-theanine is commonly available as a dietary supplement, and can be found in many health food stores and online retailers. It is generally considered safe to consume, although it is always a good idea to consult with a healthcare provider before starting any new supplement regimen. Some people may experience mild side effects, such as nausea or stomach upset, when taking L-theanine, but these are generally considered to be rare. Products also combine L-theanine with other ingredients, such as caffeine, vitamins, or herbs, to provide additional benefits. Some people may also choose to drink green or black tea, which naturally contain L-theanine, as a way to obtain the compound. It is also sometimes added to food and beverages, such as energy drinks or chocolate, as a natural flavor enhancer. It is important to carefully read the label and follow the instructions on any dietary supplement to ensure safe and effective use.



How it works


L-theanine is an amino acid that is classified as a non-protein amino acid. This means that it is not used by the body to build proteins, but rather it has other functions in the body. It is also known as a non-essential amino acid, which means that it can be synthesized by the body, so it is not essential to obtain it through the diet. L-theanine is a polar amino acid, which means that it has both a positively charged and a negatively charged end. This gives it the ability to dissolve easily in water and other polar solvents, such as alcohol. It is also a small molecule, with a molecular weight of about 131 g/mol.


L-theanine is chemically similar to other amino acids such as L-glutamine and L-tryptophan. It is an L-amino acid, which means that its chemical structure is based on a specific type of carbon atom known as a chiral carbon atom. This type of carbon atom can exist in two different forms, known as enantiomers, which are mirror images of each other. L-theanine is one of the enantiomers of theanine, and is believed to be the form that is responsible for its effects in the body.


One of the most interesting aspects of L-theanine is its potential effects on neurocognition, or brain function. Several studies have suggested that L-theanine may have positive effects on cognitive performance, including improving attention, focus, and memory. For example, a study published in the journal Nutritional Neuroscience found that L-theanine improved accuracy and speed on a task that required sustained attention.


In addition, L-theanine may also have protective effects on the brain. Some research has suggested that it may help to reduce the negative effects of stress on the brain, and may even have neuroprotective effects against age-related cognitive decline. A study published in the journal Neuropharmacology found that L-theanine protected against cognitive impairment in mice that were exposed to a neurotoxin.


The pharmacology of L-theanine is not well understood, but it is thought to work by increasing levels of neurotransmitters in the brain, such as dopamine and serotonin, which are involved in mood regulation and stress reduction. It may also have effects on brain waves, as it has been shown to increase alpha brain waves, which are associated with relaxation. The potential effects of L-theanine on neurocognition are interesting and promising, and further research is needed to fully understand its mechanisms of action and potential benefits.


One of the most commonly reported effects of L-theanine is a feeling of relaxation and calmness. Many people find that it helps to reduce anxiety and stress, and can improve overall mood. Some people may also experience a feeling of enhanced focus and concentration, as well as improved sleep quality. L-theanine is generally considered safe to consume, and is not known to have any significant side effects. However, some people may experience mild gastrointestinal upset, such as nausea or stomachache, when taking L-theanine. This is generally considered to be rare and is not a common side effect.



How it is taken


The typical way that most people use L-theanine is by taking it in capsule or tablet form. The recommended daily dose of L-theanine varies depending on individual factors such as age, sex, and weight. For adults, the typical daily dose is between 100-200 mg per day, taken once or twice daily. However, it is always a good idea to consult with a healthcare provider before starting any new supplement regimen to determine the appropriate dose for your individual needs.


There is no definitive answer to the question of the best time of day to take L-theanine, as it may vary depending on individual factors and the specific reason for taking the supplement. Some people may find that taking L-theanine in the morning helps to improve focus and concentration, while others may prefer to take it in the evening to promote relaxation and improve sleep.


In general, it is best to take L-theanine at the same time each day to help establish a consistent routine. It is also important to follow the instructions on the supplement label and to avoid taking excessive doses, as taking too much L-theanine can cause side effects such as nausea or stomach upset. It is important to consult with a healthcare provider before taking L-theanine supplements, as they may interact with certain medications or have potential side effects.




References and further reading:

  1. Yokogoshi, H., Kobayashi, M., Mochizuki, M., & Terashima, T. (1998). Effect of theanine, r-glutamylethylamide, on brain monoamines and striatal dopamine release in conscious rats. Neurochemical research, 23(5), 667-673.

  2. Kimura, K., Ozeki, M., Juneja, L. R., & Ohira, H. (2007). L-Theanine reduces psychological and physiological stress responses. Biological psychology, 74(1), 39-45.

  3. Unno, K., Tanida, N., Ishii, N., Yamamoto, H., Iguchi, K., Hoshino, M., ... & Yamada, H. (2011). Anti-stress effect of theanine on students during pharmacy practice: positive correlation among salivary α-amylase activity, trait anxiety and subjective stress. Pharmacology Biochemistry and Behavior, 99(1), 100-105.

  4. Nobre, A. C., Rao, A., & Owen, G. N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pacific journal of clinical nutrition, 17(S1), 167-168.

  5. Koo, M. I., Seo, J. H., Kim, H. J., & Kim, H. (2012). Protective effects of theanine on cognitive function and hippocampus in an Alzheimer's disease mouse model. The Korean journal of physiology & pharmacology: official journal of the Korean Physiological Society and the Korean Society of Pharmacology, 16(2), 143.