L-Theanine benefits, uses, and history

L-Theanine: Benefits, Uses, and History

L-theanine, also referred to as simply theanine, has gained significant attention for its unique ability to promote relaxation while simultaneously sharpening mental acuity. Found primarily in tea leaves, this natural compound has been a part of ancient Eastern cultures for centuries, celebrated for its ability to induce a state of calm alertness.

In recent years, research has revealed more about the potential benefits of L-theanine, including antioxidant, anti-inflammatory, neuroprotective, metabolic regulatory, cardiovascular protective, and anti-obesity effects. 1

This unique effect has made L-theanine an ideal health supplement. But how can you leverage it in your wellness routine, and what should you know about it ahead of time? Let's delve into its history, origins, potential health benefits, uses, recommended dosage, and availability.

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The Definition: L-theanine is a non-protein water-soluble amino acid found in the leaves of green, as well as certain mushrooms.

The Process: The best conditions for extracting theanine from green tea using water were discovered to be extraction at 80°C for 30 minutes with a water-to-tea ratio of 20:1 mL/g and a tea particle size of 0.5-1 mm, according to the Journal of Separation Science.

How To Take: Typically, L-theanine supplements are commonly found in 200-mg tablet form, which can be taken daily. It can also be taken in a variety of forms, including capsules, powder, and liquid extracts. 

History: The history and origins of L-theanine can be traced back to the rich tea-drinking traditions of ancient Eastern cultures, particularly in China and Japan. It was first identified in 1949 and has since been studied extensively for its potential health benefits.

How L-Theanine Works

L-theanine is known for its calming effects on the body and mind, and its ability to improve cognitive performance.  It is believed to influence brain chemistry and function in several ways. It can increase the production of alpha brain waves, which are associated with a state of wakeful relaxation and focused attention. 2 It also modulates the levels of neurotransmitters in the brain, including serotonin, dopamine, and GABA, which play important roles in mood regulation, stress response, and cognitive function.

What is L-Theanine

What Are The Benefits Of L-Theanine? 

L-theanine offers a range of benefits that have made it a popular choice among individuals seeking natural ways to enhance their well-being. Here are some of the benefits you can expect:

Anxiety And Stress Relief

L-theanine is renowned for its notable benefits in promoting relaxation and combating stress, a popular choice among those seeking a natural solution. It has gained recognition as a relaxing agent that doesn't induce sedation, allowing individuals to effectively cope with stress without experiencing feelings of lethargy or fatigue.

In a study of people with generalized anxiety disorder, L-theanine was found to reduce symptoms of anxiety significantly. 3

Increased Focus

In a small-scale study, researchers discovered that a combination of L-theanine (97 mg) and caffeine (40 mg) had a positive impact on the ability of young adults to concentrate during demanding tasks. 4

Blood Pressure Management 

Another potential benefit of L-theanine is its impact on blood pressure management. Studies have shown that regular consumption of L-theanine can help to reduce blood pressure levels, as well as to improve the body's response to stress. 5

Interested in incorporating L-theanine into your routine? We here at FOCL have a wide range of products available that leverage the potential of this botanical compound. Here are a few products you should check out if you’re interested in L-theanine. 

  • Chill Out CBD + THC Gummies: Our Full Spectrum + line of products incorporates more THC into the formulation, helping users relax and achieve their goals with ease. Our Chill Out CBD + THC Gummies are delicious Sour Raspberry edibles featuring 25mg of CBD and 3mg of CBD per gummy. An added 100mg of L-theanine enhances mental clarity and focus. 
  • Deep Sleep CBD + THC Gummies: Getting to sleep isn’t easy for everyone, which is why we carefully crafted our Deep Sleep CBD + THC Gummies. Packing a delicious Sour Blue Raspberry flavor, our formulation combines 25mg of CBD, 15mg of CBN, 2.5mg of THC, 1mg of melatonin, and L-theanine to give you everything you need to get the rest you deserve. 
  • Day: Our FOCL Day capsules are for those looking for a feel-good day every day. Focused on fostering clarity, focus, and balance, this blend is formulated with 400mg of organic Lion’s Mane mushrooms to support cognitive performance, 150mg of organic Bacopa Monnieri to improve concentration and attention, 50mg of Rhodiola Rosea to fight fatigue and keep you energized, 5mg of vitamin B6 to support mood and overall brain health, 150mg of L-theanine to support concentration as well as memory and focus, and 10mg of premium hemp CBD to support holistic health. 


What are the uses of L-theanine?

L-theanine is widely used in many different ways, both for its calming and cognitive-enhancing effects. It is commonly used to reduce stress and anxiety, improve sleep quality, and increase mental clarity and focus. It has also been used to improve symptoms of depression, reduce blood pressure, and enhance the immune system (although it’s advisable to speak with a healthcare professional if you have issues in these areas). 

How do you take L-theanine?

L-theanine can be taken in a variety of forms, including capsules, tablets, powder, and liquid extracts. You can even find some of these forms here in our CBD product. When taking the supplement form, read and follow the instructions provided on the product packaging or consult a healthcare professional for guidance specific to the L-theanine supplement you are using.

What is the proper L-theanine dosage? 

L-theanine is not a medication; therefore, there are no established official guidelines specifying the recommended dosage. However, note that L-theanine is generally considered safe and the risk of an overdose is low.

Typically, L-theanine supplements are commonly found in 200-mg tablet form, which can be taken daily. Stick to the suggested dosage on the supplement you’re taking so as to avoid taking too much in one sitting. Also, make sure to check any other supplements you’re taking to ensure you’re not accidentally absorbing too much L-theanine elsewhere.

What is the availability and cost of L-theanine?

L-theanine is readily available in many health food stores, vitamin shops, and pharmacies both online and offline. L-theanine is available in a variety of forms, including capsules, tablets, liquid extracts, and powders. It can also be found in some teas and foods, and it is considered to be a safe and affordable supplement.

The cost of L-theanine may vary depending on the form and brand. Generally, it is more affordable than other nootropics, with prices ranging from $10 to $50 for a month's supply. Note that these prices may vary significantly depending on the brand, formulation (such as incorporating additional ingredients into the supplement), and other factors. 

Is it okay to take L-theanine daily?

Yes, L-theanine is generally considered safe for daily use and is well-tolerated by most individuals. However, it's always advisable to consult with a healthcare professional before starting any new dietary supplement, as they can provide personalized recommendations based on your specific health needs and considerations.

Is L-theanine safe for kidneys?

L-theanine is generally considered safe for kidneys when used in appropriate doses. However, as with any dietary supplement or medication, it's important to use L-theanine according to the recommended dosage. Too much of a good thing can often be a bad thing.

What foods are high in theanine?

Theanine is naturally found in green tea leaves, as well as certain mushrooms. While tea is the most abundant source of theanine, other types of tea, such as black tea and white tea also contain varying amounts of this amino acid. However, green tea is arguably your best bet for getting more theanine. There are no food items that contain the high-amounts of theanine you might want.

Who should not take theanine? 

L-theanine is generally safe for most people. However, it is not recommended that pregnant or breastfeeding women take L-theanine. Also, if you are taking any medication, consult with your doctor before taking L-theanine, as it may interact with some medications. If you fall outside of these exceptions, the likelihood that you’ll have a negative reaction is very rare. 

Can I take L-theanine with other vitamins?

Yes, L-theanine can generally be taken with other vitamins and supplements. It is considered safe to combine L-theanine with most commonly consumed vitamins and minerals. However, seek advice from your healthcare provider prior to incorporating any supplement into your routine, especially if it combines multiple ingredients. 

Also, make sure to check for sneaky ingredients that could pose a health issue, like caffeine (caffeine is not good to take in large quantities). As long as you’re responsible for your supplement consumption and carefully track what types of supplements you’re getting from various sources, you should be fine!


  1. Li, M.-Y., Liu, H.-Y., Wu, D.-T., Kenaan, A., Geng, F., Li, H.-B., Gunaratne, A., Li, H., & Gan, R.-Y. (2022). L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications. Frontiers in Nutrition, 9. https://doi.org/10.3389/fnut.2022.853846
  2. 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 Suppl 1, 167–168. https://pubmed.ncbi.nlm.nih.gov/18296328/
  3. ‌Sarris, J., Byrne, G. J., Cribb, L., Oliver, G., Murphy, J., Macdonald, P., Nazareth, S., Karamacoska, D., Galea, S., Short, A., Ee, C., Birling, Y., Menon, R., & Ng, C. H. (2019). L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trial. Journal of Psychiatric Research, 110, 31–37. https://doi.org/10.1016/j.jpsychires.2018.12.014
  4. Giesbrecht, T., Rycroft, J. A., Rowson, M. J., & De Bruin, E. A. (2010). The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutritional Neuroscience, 13(6), 283–290. https://doi.org/10.1179/147683010x12611460764840
  5. Yoto, A., Motoki, M., Murao, S., & Yokogoshi, H. (2012). Effects of L-theanine or caffeine intake on changes in blood pressure under physical and psychological stresses. Journal of Physiological Anthropology, 31(1). https://doi.org/10.1186/1880-6805-31-28