Suntheanine is a patented or a trademarked version of L-theanine, an amino acid predominantly found in tea leaves—particularly green tea (Camellia sinensis). [1]

Nowadays, L-theanine is becoming more popular due to its alleged health advantages, such as its potential to enhance relaxation in people’s bodies, as well as help reduce stress levels. In particular, Suntheanine is a highly refined and saturated version of L-theanine. [2]

In this article, we will look at everything you need to know about Suntheanine, such as its uses, benefits, possible side effects, and more. 

What exactly is Suntheanine?

Suntheanine is a proprietary type of L-theanine created by the Japanese firm Taiyo Kagaku. It is a bioactive component extracted from green tea leaves using a patented enzymatic fermentation technique. This technique delivers a high-purity version of L-theanine that is standardized and guaranteed to be consistent in every dose. [3]

What is the intended use of Suntheanine?

When used as a nutritional supplement, Suntheanine is often used to enhance relaxation, alleviate stress, and enhance sleep quality. It is also used to maintain cognitive function, improve concentration and attention, and reduce anxiety and depression in people with these symptoms. [2][4][5]

What are the benefits of Suntheanine?

Now that you know how much intriguing possibilities Suntheanine has when utilized as a component in dietary supplements, we’ll go over all of the advantages this proprietary form of L-theanine has become known for in this section of the article:

Aids in reducing stress and boosting overall relaxation

The first and most well-known benefit of Suntheanine is its ability to generate more alpha brain waves—which are connected with a relaxed but not drowsy condition. It promotes a calm and concentrated mental state, which reduces anxiety and tension in our brain. [5]

Boosts cognitive ability

Another popular advantage of Suntheanine is it can help boost cognitive performance, such as attention, focus, and memory. Proper continued usage of this supplement may improve learning abilities and mental clarity. [4]

Help improve sleeping habits

Suntheanine can also aid in improving sleep quality by lowering anxiety and encouraging relaxation without making you dizzy. And due to its lack of sedative properties, it can help a lot in improving your sleeping patterns. [6]

Enhances mood

And one more popular benefit of Suntheanine is its mood-enhancing capabilities. According to some research, using Suntheanine medication can potentially lower signs and symptoms of anxiety and boost general emotional well-being. [7]

Is Suntheanine effective?

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Suntheanine has been shown in several clinical tests to effectively provide the intended effects we mentioned earlier. It has been demonstrated that the increase of alpha brain wave activity, induces calm, and improves cognitive performance. [4][5][6]

But as always, it is necessary to remember that individual reactions to Suntheanine vary from person to person. So before planning on taking it as a medical supplement, always contact a healthcare practitioner first.

Does Suntheanine have any recognized side effects?

Generally speaking, the use of Suntheanine drugs is considered safe for most people when taken at the prescribed dosages. Its usage is generally accepted in the medical scene, and it also doesn’t make you drowsy or addicted. Although it is worth mentioning that on rare occasions, some side symptoms, such as stomach pain or headaches, may occur for some people. [8][9]

Dose recommendations for Suntheanine vary based on the person taking the medication and their intended use. A normal dose varies from 100mg to 200mg per day as a general guideline when used for relaxation and stress reduction purposes. And then, a dosage of 200mg to 400mg per day may be more suited for cognition assistance and focused attention. [10]

However, it is crucial to follow the recommendations on the product’s label or get individualized guidance from a healthcare expert.

What exactly is the key difference between Suntheanine and L-theanine?

Suntheanine and L-theanine are both amino acids. However, the main difference is that Suntheanine is a proprietary and extremely refined version of L-theanine. Additionally, the patented fermentation process used to produce Suntheanine guarantees a constant and more standardized quality medicine, which may not be available in generic L-theanine supplements. [11][12]

How long does Suntheanine take to work?

The first signs of effects can vary between individuals. Some people may feel the effects of Suntheanine within the first 30 to 60 minutes, whereas some may need to wait longer. In order to assess its effectiveness for you, you must be patient and persistent with your usage. [13]

Can I use Suntheanine on a daily and long-term basis?

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Suntheanine is typically safe for everyday usage and can be used for an extended period of time. However, it is best to stick to the suggested dosages and review your needs on a regular basis with the help of a healthcare professional. [14]

Can Suntheanine be used with other medications?

Suntheanine is typically compatible with the majority of drugs. However, before taking it, it is basic knowledge to always speak with a healthcare practitioner or pharmacist first—especially if you are diagnosed with serious medical conditions or if you are already prescribed with any type of medication. [15]


Suntheanine, a specialized form of L-theanine derived from green tea leaves, offers a range of potential benefits for relaxation, stress reduction, cognitive function, and sleep quality. It has been thoroughly researched and has yielded encouraging outcomes in clinical studies.

While individual responses on the drug may vary, Suntheanine is generally well-tolerated and considered safe when taken at recommended dosages. It is important to note that Suntheanine is a dietary supplement and should not be used as a replacement for medical treatment or therapy.


Yes, Suntheanine is generally thought to be safe when taken by children. As of recent testing, Suntheanine has no components that can cause any complications in kids.
While Suntheanine is generally considered safe, it is highly suggested that you contact your pediatrician before taking any dietary supplements if you are pregnant, nursing, or intending to become pregnant.
While it is true that Suntheanine is produced from tea leaves—it still remains caffeine-free! As a result, those who are sensitive to tea or caffeine are expected to tolerate it fairly well. However, if you have any specific medical concerns, you should contact your doctor first before using it.

Disclaimer: This article is only a guide. It does not substitute the advice given by your healthcare professional. Before making any health-related decision, consult your healthcare professional.

Editorial References And Fact-Checking

  1. Camellia sinensis (Assam Tea, Tea Camellia, Tea Plant, Tea Tree Camellia) | North Carolina Extension Gardener Plant Toolbox. (n.d.).
  2. Kunugi, H., Hidese, S., Ogawa, S., Ota, M., Yasukawa, Z., & Ozeki, M. (2019). Effects of Chronic L-theanine on Stress-related Symptoms and Cognitive Function in a Non-clinical Population: A Randomized Controlled Trial (P06-106-19). Current Developments in Nutrition, 3(Suppl 1), nzz031.P06-106-19.
  3. Taiyo GmbH. (2020, October 5). Suntheanine – Pure L-Theanine powder -Taiyo GmbH.
  4. Baba, Y., Inagaki, S., Nakagawa, S., Kaneko, T., Kobayashi, M., & Takihara, T. (2021). Effects of l-Theanine on Cognitive Function in Middle-Aged and Older Subjects: A Randomized Placebo-Controlled Study. Journal of medicinal food, 24(4), 333–341.
  5. Hidese, S., Ota, M., Ozawa, H., Okubo, T., & Kunugi, H. (2019). An Open-label Clinical Study of Chronic L-theanine Supplementation in Patients with Major Depressive Disorder (P12-007-19). Current Developments in Nutrition, 3(Suppl 1), nzz035.P12-007-19.
  6. Unno, K., Noda, S., Kawasaki, Y., Yamada, H., Morita, A., Iguchi, K., & Nakamura, Y. (2017). Ingestion of green tea with lowered caffeine improves sleep quality of the elderly via suppression of stress. Journal of clinical biochemistry and nutrition, 61(3), 210–216.
  7. Dodd, F. L., Kennedy, D. O., Riby, L. M., & Haskell-Ramsay, C. F. (2015). A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood. Psychopharmacology, 232(14), 2563–2576.
  8. Halson, S. L., Shaw, G., Versey, N., Miller, D. J., Sargent, C., Roach, G. D., Nyman, L., Carter, J. M., & Baar, K. (2020). Optimisation and Validation of a Nutritional Intervention to Enhance Sleep Quality and Quantity. Nutrients, 12(9), 2579.
  9. Barrett, J. R., Tracy, D. K., & Giaroli, G. (2013). To sleep or not to sleep: a systematic review of the literature of pharmacological treatments of insomnia in children and adolescents with attention-deficit/hyperactivity disorder. Journal of child and adolescent psychopharmacology, 23(10), 640–647.
  10. Suntheanine. (2023, April 4). L-theanine for Sleeping: Benefits of L-Theanine – Suntheanine.
  11. 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, 853846.
  12. Saeed, M., Khan, M. S., Kamboh, A. A., Alagawany, M., Khafaga, A. F., Noreldin, A. E., Qumar, M., Safdar, M., Hussain, M., Abd El-Hack, M. E., & Chao, S. (2020). L-theanine: an astounding sui generis amino acid in poultry nutrition. Poultry science, 99(11), 5625–5636.
  13. Lardner, A. L. (2014). Neurobiological effects of the green tea constituent theanine and its potential role in the treatment of psychiatric and neurodegenerative disorders. Nutritional neuroscience, 17(4), 145-155.
  14. Johnson, B., PhD. (2022). L-Theanine Side Effects: Is Theanine safe for long-term use? | VAGA. VAGA.
  15. Saeed, M., Naveed, M., Arif, M., Hamid, M., Manzoor, R., El-Hack, M. E. A., Alagawany, M., Tiwari, R., Khandia, R., Munjal, A., Karthik, K., Dhama, K., Iqbal, H. M., Dadar, M., & Sun, C. (2017). Green tea (Camellia sinensis) and l-theanine: Medicinal values and beneficial applications in humans—A comprehensive review. Biomedicine & Pharmacotherapy, 95, 1260–1275.


  • Elijah Redoble

    Elijah enjoys creating content that educates and entertains at the same time. During the health-content writing process, Elijah takes extra care and precaution to craft research-backed articles that are helpful, educational, and relatable to readers from various walks of life. LinkedIn

  • Kim Monasterial, BSN

    Kim is a Registered Nurse and has been a medical freelance writer for more than six years. Starting off as a writer, Kim moved to proofreading and editing all the articles posted on HealthPlugged. She’s an enthusiast for health and wellness, being one to keep herself fit and adventurous for outdoor activities. LinkedIn


Elijah enjoys creating content that educates and entertains at the same time. During the health-content writing process, Elijah takes extra care and precaution to craft research-backed articles that are helpful, educational, and relatable to readers from various walks of life. LinkedIn