Suntheanine is a proprietary form of L-Theanine. This amino acid is naturally found in green tea leaves and has been noted for a number of cognitive effects.
It is predominantly used as a relaxation supplement, believed to support feelings of calm and contentment. L-Theanine supplements and Suntheanine are commonly used in nootropic stacks, and as natural anti-stress remedies.
This component of tea was discovered in 1949 and has been approved in Japan since 1964 for unlimited use in foods including chocolates, soft drinks, and herbal teas.It is also noted for providing a unique savory taste and flavor to green tea infusions.
L-Theanine is further known to be an analog to Glutamate and Glutamine. Suntheanine is sold in the US as a dietary supplement and classified by the FDA as an ingredient on the generally regarded as safe (GRAS) list. This means it has a very low risk of negative side effects.
Research has show this supplement to have positive effects on alpha brain waves. This supplement was awarded the 1998 Food Ingredient Research Award and is protected by over 40 different US and international patents for its various physiological efficacies and production processes.
Suntheanine is available in the US as a dietary supplement only, and the FDA has not approved Suntheanine as a drug to prevent or treat any conditions.



- Supports focus, attention & mood
- Helps to reduce stress & anxiety
- Neuroprotective & increases NGF
Suntheanine Effects
Related Topics
The main method of action of this supplement involves Suntheanine crossing over the blood-brain barrier and entering into the central nervous system.
Once this occurs, it tends to have a moderating effect upon alpha brain waves. Higher levels of alpha brain waves are associated with relaxation while still maintaining a feeling of calm alertness.
It has also been noted to reduce or decrease beta brain waves, which are typically related to being in an excited state. Another believed method of action for this supplement is boosting the activity of existing neurotransmitters such as Serotonin, Dopamine, and GABA.
GABA is regarded as the chief inhibitory neurotransmitter within the human brain. Suntheanine helps to increase the release of this chemical which in turn reduces feelings of stress and anxiety. GABA regulates over-excited neurons, causing them to fire at a normalized rate.
This promotes sensations of tranquility and well-being in the mind. This is also one of the reasons why people can drink caffeinated green tea and avoid the jitters or nervousness typically associated with stimulants like coffee that contain caffeine alone.
Suntheanine Benefits
There are a number of nootropic benefits which have become associated with Suntheanine and L-Theanine over the years. Most notably these supplements are said to induce an overall feeling of calm and relaxation.
Reviews characterized this effect of Suntheanine by pointing out that you still remain very mentally alert when using it. Instead of a sleepy or fatigued sense of relaxation, you will likely experience a peaceful state of focus and awareness.
Another related benefit is that this supplement is said to eliminate stress and reduce anxious thoughts. As your excitatory beta brain waves are moderated, it follows that feelings of stress will dissipate.
It is also thought that Suntheanine helps to boost levels of another neurotransmitter within the brain, Dopamine.
This chemical is considered to regulate mood and movement and is described as a “feel good” neurotransmitter. It may further modulate some of the stimulatory neurotransmitters which can contribute to a feeling of anxiousness.
Suntheanine is a highly purified form of Theanine and is considered to be pharmaceutical grade. One of the main differences between the two is that Suntheanine is considered a more powerful antioxidant. It is capable of removing dangerous elements like free radicals from cells in the brain and body.
Suntheanine may also boost the immune system and promote detoxification throughout the body. Your overall health may be improved and the boost to the immune system may make you less prone to catching some diseases like the cold or flu.
Suntheanine Dosage
The commonly recommended dosage range for Suntheanine is between 100 and 250 mg per day. Of course, supplements do effect each person slightly differently, so it is best to always start at the lowest effective dose. Proper dosage depends on many different factors, and it is recommended that you speak with your doctor to determine the best dosage for your personal needs.
Although this might call for a bit of experimentation, the suggested way to start is to take somewhere between 50 and 100 mg per day and carefully observe any side effects. Only consider increasing the dose once you are familiar with the effects of Suntheanine on your physiology.
Suntheanine Side Effects
This supplement is on the FDA generally regarded as safe list (GRAS), and it is very well-tolerated in healthy adults. However, there are still a small number of rare side effects that have become associated with Suntheanine.
Fortunately most are mild consisting of headaches, insomnia, irritability, diarrhea, and heartburn. These are usually only reported in higher doses.
There is also some concern about using this nootropic in conjunction with sedatives, cholesterol lowering medications, blood pressure lowering drugs, and drugs used to treat depression and anxiety. If you are on any such medications, please speak to a doctor before taking Suntheanine or any other nootropic compound.
Suntheanine Review
If you have experienced positive effects from using L-Theanine in your nootropic stack, Suntheanine is considered a more concentrated version that may offer additional benefits. It is distinguished for promoting feelings of calm alertness, enabling you to maximize your productivity while still managing stress and anxious thoughts.
Suntheanine may also have a positive mood enhancement effect due to the increase in Dopamine levels in the brain. Furthermore, Suntheanine is an immune system booster and offers antioxidant benefits for your brain cells.
If you are curious about trying this nootropic, it is a worthwhile experiment: Suntheanine is safe and unlikely to cause side effects in healthy individuals.
- Tadesse A, Hymete A, Bekhit AA, Mohammed SF. Quantification of total polyphenols, catechin, caffeine, L-theanine, determination of antioxidant activity and effect on antileishmanial drugs of ethiopian tea leaves extracts. Pharmacognosy Res. 2015
- Kimura K, Ozeki M, Juneja LR, Ohira H. L-Theanine reduces psychological and physiological stress responses. Biol Psychol. 2007
- Camfield DA, Stough C, Farrimond J, Scholey AB. Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis. Nutr Rev. 2014
- Kurihara S, Shibahara S, Arisaka H, Akiyama Y. Enhancement of antigen-specific immunoglobulin G production in mice by co-administration of L-cystine and L-theanine. J Vet Med Sci. 2007
- Narukawa M, Toda Y, Nakagita T, Hayashi Y, Misaka T. L-Theanine elicits umami taste via the T1R1 + T1R3 umami taste receptor. Amino Acids. 2014
- Jiang W, Gao M, Sun S, Bi A, Xin Y, Han X, Wang L, Yin Z, Luo L. Protective effect of L-theanine on carbon tetrachloride-induced acute liver injury in mice. Biochem Biophys Res Commun. 2012
- Kurihara S, Hiraoka T, Akutsu M, Sukegawa E, Bannai M, Shibahara S. Effects of (L)-cystine and (L)-theanine supplementation on the common cold: a randomized, double-blind, and placebo-controlled trial. J Amino Acids. 2010
Article last updated on: March 16th, 2018 by Nootriment
2 Comments
Hello,
Just wanted to know for how long I can take Suntheanine. Is it safety to be consumed daily?
Best Regards,
Daniel
Hi Daniel,
Thanks for your question! There are no definitive guidelines regarding how long you can take Suntheanine for. We do know that L-Theanine (from which it is derived) is safely used for long periods of time. Anyone who drinks Green Tea daily gets a small dosage of this supplement. One study examined the use of 2 x 200 mg daily dosages of Suntheanine over 6 weeks and saw no side effects. That might be a good guide for you to follow, though this information comes from the manufacturer and ideally it should be verified by an independent third party. Here is the link to that information plus the relevant section of the article below: suntheanine.com/from-the-experts/
“L-theanine is a naturally occurring molecule that is present in the diets of children around the world where tea is a consumed and no concerns have ever been raised about its safety. Suntheanine, which is a purified form of L-theanine produced by a fermentation process, has also been approved as a food ingredient and nutritional supplement in some countries for many years and in these countries it has a perfect safety record. Recently, I was in charge of a large double blind study in which 200mg of Suntheanine was consumed twice per day for six weeks in boys 8-12 years with attention deficit disorder. No side effects were reported in any of these boys and I now view Suntheanine as one of the safest natural products that can be given to a child.“