The Nootropics Library: L-Theanine

Everything You Need to Know About L-Theanine and Camellia sinensis

General Information

Scientific Name: [L-Theanine: r-glutamylethylamide, Suntheanin] [Camellia sinensis – the Plant Containing L-Theanine; of the Theaceae Family]

Any Other Names: Theanine, Constituent of Camellia sinensis, Green Tea

Primary Constituents: L-Theanine

Country or Region of Origin: East Asia and Southwestern China

Known Uses: Reduce Stress and Anxiety, Lowers Elevated Blood Pressure, Increases Concentration and Focus, Promotes Relaxation

General History & Introduction

Camellia sinensis is better known as “tea” and is the second highest consumed beverage on the planet (Twilley & Lall, 2018). The Camellia sinensis plant grows as an evergreen shrub around 3-5 feet tall with dark, rough leaves and sweet-smelling, white flowers (Chevallier, 2016).  It is typically found in India, China, and Sri Lanka, where it has established itself as a staple herbal tea even in the earliest of cultures. There are a lot of ancient, cultural rituals in many Asian countries surrounding the drinking of the herbal tea (2016). Each tea plant produces enough leaves to be picked up to 4 times within a year (Shivashankara et al., 2014).

Camellia sinensis also has a long history of use in Ayurvedic medicine (Chevallier, 2016). It has also been well-accepted throughout Indian culture as an herbal tea (2016). And although Camellia sinensis has a lot of great benefits, one of its amino acid derivatives, L-Theanine, is primarily responsible for the plant’s nootropic effects (2016). L-Theanine is well known for its favorable effects on cognitive performance, emotional state and mood, sleep, and a variety of other health benefits (Türközü & Şanlier, 2017).

Important Note: L-Theanine is a derivative of Camellia Sinensis, which is commonly used to make green tea. Both L-Theanine and Camellia Sinensis offer profound cognitive and relaxation effects, only L-Theanine is considered a nootropic and Camellia Sinensis is usually only consumed as a tea. This article will reveal the positive benefits of items, and how their effects may compare and contrast.

Nootropic Benefits of L-Theanine and Camellia sinensis

Concentration, Focus, and Cognitive Benefits (both L-Theanine and Camellia sinensis)

L-Theanine has always been used for its cognitive performance enhancing capability, however, modern studies have begun to record its significant effect on measurable attributes.  For example, one study has measured the chemical’s effects on concentration and learning ability with encouraging results and future propositions for improving the chemical’s value in the brain (Vuong et al., 2011). The nootropic possesses an innate ability to increase cerebral blood flow, especially when it is used alongside caffeine (Dodd et al., 2015). This contribution to brain health is one of the main factors in its reported cognitive benefits (Dodd et al., 2015).


The nootropic provides the brain with increased subjective alertness and improved cognitive function (Giesbrecht et al., 2010). It is one of the primary nootropics benefiting from use alongside another.  In other words: L-Theanine works better when it is used with Caffeine. For example, one study on the combination of L-Theanine and Caffeine found participants to have significantly improved focus and attention-spans during a “demanding cognitive task” (2010).

Reduces Stress and Anxiety, Promotes Relaxation (both L-Theanine and Camellia sinensis)

L-Theanine has been revered throughout Eastern cultures for thousands of years for its ability to reduce oxidative stress and provide focused, calming effects (Ross, 2014). These antioxidant properties are present when the plant is brewed in tea form, as well as within L-Theanine supplements (Chevallier, 2016). There are studies which have shown the primary constituent has a significant positive effect on behavior and mood (Dodd et al., 2015).

One recent, randomized, controlled-trial suggested that L-Theanine can significantly relieves stress-related ailments and promotes overall mental health (Hidese et al., 2019). And some studies suggest that L-Theanine can increase certain neurotransmitters in the brain, which are responsible for promoting relaxation and regulating mood (Nathan et al., 2006). These neurotransmitters include dopamine, serotonin, and GABA (2006).

Digestive Treatments (both L-Theanine and Camellia sinensis)

Gut Flora are microorganisms (bacteria) which live in the intestines and aide in digestion activities. Some recent research suggests that L-Theanine may have the potential to improve Gut Flora in the digestive tract while also limiting the growth and spread of harmful bacteria (Saeed et al., 2019).  It is purportedly also able to reduce risks of infections within digestive organs (Li et al., 2016).  Some research even suggests the chemical can entirely prevent some digestive disorders (Wang et al., 2012).

One study has suggested that drinking unfractionated green tea can help prevent gastrointestinal disorders (Koo & Cho, 2004). More recent research has revealed the polysaccharides from Camellia sinensis flowers are able to regulate gut health (Chen et al., 2019). This same study suggested that the plant also ameliorated cyclophosphamide-induced immunosuppression (2019).

Other Benefits (both L-Theanine and Camellia sinensis)


Camellia sinensis herbal tea has long been used to treat a variety of skin and inflammation conditions (Chevallier, 2016).  It also offers many anti-bacterial benefits. The constituent L-Theanine is great for regulating and improving the quality of sleep (Türközü & Şanlier, 2017). It has also been proven to have positive effects on cancer, cardiovascular disease, and obesity.  The nootropic can even reduce the symptoms of the common cold (2017). Some research has shown that regular consumption of Camellia sinensis can reduce risk of pancreatic cancer (Wang et al., 2012).  Similarly, L-Theanine has been shown to have the potential to prevent and manage many different types of cancers (2012).

And one study revealed L-Theanine’s potential to improve immune function (Li et al., 2016). The chemical has been shown to possess an ability to improve nutrient absorption in the gut (Yan et al., 2017). Vitamins and minerals are literally absorbed better with L-Theanine, improving overall health (2017).

Dosing and Usage Information

Normally, only the leaves and buds of the Camellia sinensis plant are used, and this includes in the extraction of primary constituent, L-Theanine (Chevallier, 2016). Dietary supplements typically contain a maximum of 400 mg of L-Theanine extract.

Side Effects

Although more research is still required to draw ultimate consensus, one recent study on the safety and effects of using L-Theanine on a regular basis revealed the chemical as reliable and generally accepted as safe, even when consumed in larger quantities (Türközü & Şanlier, 2017). That said, while uncommon, some side effects may include headaches, irritability, and nausea (Giesbrecht et al., 2010).

Other Important Information

Sometimes Camellia sinensis is mixed with other herbs to create intricate herbal tea concoctions.  Cinnamon is one of the most popular additives (Chevallier, 2016).  The plant is used to produce all kinds of teas, including the traditional black, oolong, and green teas (Shivashankara et al., 2014).

The primary constituent responsible for the nootropic benefits of the tea, L-theanine, is also responsible for the flavorful taste of the tea (Vuong et al., 2011).


L-Theanine and its parent plant, Camellia sinensis, are extremely effective brain-boosters and have been well-known throughout many cultures as such.  They also offer relaxation-inducing effects.  L-Theanine’s nootropic benefits are constantly being investigated and backed by a growing archive of studies and empirical data. For this reason, L-Theanine has become one of the more popular nootropics, especially in Western cultures. And its effects on cognitive function and stress make it a great addition to most nootropic stacks.

A Note from NooFiles

This article is intended to be used for information only.  We want to remind you that consulting your physician is recommended before adding any dietary supplement of any kind to your daily regimen.


Chen, D., Chen, G., Ding, Y., Wan, P., Peng, Y., Chen, C., Ye, H.,, Zeng, X., and Ran, L. (2019). Polysaccharides from the flowers of tea (Camellia sinensis L.) modulate gut health and ameliorate cyclophosphamide-induced immunosuppression. Journal of Functional Foods. Vol. 61. DOI:

Chevallier, A. (2016). Encyclopedia of Herbal Medicine. Third Edition. DK Publishing. New York, New York. ISBN 978-1-4654-4981-8

Dodd, F., Kennedy, D., Riby, L., and Haskell-Ramsay, C. (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 (Berl). Vol. 232(14). Pp. 2563-76. DOI: 10.1007/s00213-015-3895-0

Giesbrecht, T., Rycroft, J., Rowson, M., and De Bruin, E. (2010). The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutr Neurosci. Vol. 13(6). Pp. 283-90. DOI: 10.1179/147683010X12611460764840

Hidese, S., Ogawa, S., Ota, M., Ishida, I., Yasukawa, Z., Ozeki, M., and Kunugi, H. (2019). Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. Vol. 11(10). Pp. 2362. DOI: 10.3390/nu11102362

Koo, M., and Cho, C. (2004). Pharmacological effects of green tea on the gastrointestinal system. Eur J Pharmacol. Vol. 500(1-3). Pp. 177-85. DOI: 10.1016/j.ejphar.2004.07.023

Ross, S. (2014). L-theanine (suntheanin): effects of L-theanine, an amino acid derived from Camellia sinensis (green tea), on stress response parameters. Holist Nurs Pract. Vol. 28(1). Pp. 65-8. DOI: 10.1097/HNP.0000000000000009

Saeed, M., Yatao, X., Tiantian, Z., Qian, R., and Chao, S. (2019). 16S ribosomal RNA sequencing reveals a modulation of intestinal microbiome and immune response by dietary L-theanine supplementation in broiler chickens. Poult Sci. Vol. 98(2). Pp. 842-854. DOI: 10.3382/ps/pey394

Li, C., Tong, H., Yan, Q., Tang, S., Han, X., Xiao, W., and Tan, Z. (2016). L-Theanine Improves Immunity by Altering TH2/TH1 Cytokine Balance, Brain Neurotransmitters, and Expression of Phospholipase C in Rat Hearts. Medical science monitor : international medical journal of experimental and clinical research. Vol. 22. Pp. 662–669. DOI:

Nathan, P., Lu, K., Gray, M., and Oliver, C., (2006). The Neuropharmacology of L-Theanine(N-Ethyl-LGlutamine). Journal of Herbal Pharmacotherpay. Vol. 6(2). Pp. 21-30. DOI: 10.1080/J157v06n02_02

Shivashankara, A., and Baliga, M. (2014). Polyphenols in Chronic Diseases and their Mechanisms of Action Polyphenols in Human Health and Disease. Academic Press. ISBN: 978-0-12-398456-2. DOI:

Türközü D., and Şanlier, N. (2017).  L-theanine, unique amino acid of tea, and its metabolism, health effects, and safety. Crit Rev Food Sci Nutr. Vol. 57(8). Pp. 1681-1687. DOI: 10.1080/10408398.2015.1016141

Twilley, D., and Lall, N. (2018). Are Medicinal Plants Effective for Skin Cancer? Medicinal Plants for Holistic Health and Well-Being. Academic Press. ISBN: 978-0-12-812475-8. DOI:

Vuong, Q., Bowyer, M., and Roach, P. (2011). L-Theanine: properties, synthesis and isolation from tea. J Sci Food Agric. Vol. 91(11). Pp. 1931-9. DOI: 10.1002/jsfa.4373

Wang, J., Zhang, W., Sun, L., Yu, H., Ni, Q., Risch, H., and Gao, Y. (2012). Green tea drinking and risk of pancreatic cancer: A large-scale, population-based case–control study in urban Shanghai. Cancer Epidemiology. Vol. 36(6). Pp. e354-e358 DOI:

Yan, Q., Tong, H., Tang, S., Tan, Z., Han, X., and Zhou, C. (2017). L-Theanine Administration Modulates the Absorption of Dietary Nutrients and Expression of Transporters and Receptors in the Intestinal Mucosa of Rats. BioMed research international. DOI:

The Nootropics Library: Ginkgo Biloba

Everything You Need to Know About Ginkgo Biloba

General Information

Scientific Name: Ginkgo Biloba (from the Ginkgoaceae family)

Any Other Names: Maidenhair Tree, Bai Guo (Chinese)

Primary Constituents: Bilobalides, Ginkgolides, Flavonoids

Country or Region of Origin: Native to China, Also Cultivated in France, South Carolina (United States)

Known Uses: Memory, Concentration, Circulatory and Blood Flow Issues, Antioxidant, Anti-inflammatory, Anti-allergenic, Asthma, Dementia, Depression, and More

General History & Introduction

Ginkgo is one of the oldest trees on the planet, if not the oldest, with the first growing dating beyond 190 million years old (Chevallier, 2016).  It has found its place in ancient, traditional Chinese medicine. Ginkgo’s medical and therapeutic uses have been well-researched in modern times as well.  In fact, it is one of the most widely used medicinal herbs in the Western world (Roland & Nergård, 2012). The leaves are typically turned into an extract which can be used to treat a variety of ailments and conditions. Some of these maladies include but are not limited to circulation and blood flow issues, asthma, allergies, weak bladder, incontinence, anti-inflammatory, antispasmodic, multiple sclerosis, dementia, Alzheimer’s disease, depression, and even glaucoma (2016).

Nootropic Benefits of Ginkgo Biloba

Memory, Concentration, Brain Booster


Ginkgo Biloba has been used for thousands of years for its studied ability to improve memory, concentration, and overall brain function.  A lot of the plant’s contributions in this realm can be traced to its benefits to cerebral blood flow and circulation (Chevallier, 2016).  Improving cerebral circulation gives memory and concentration a giant boost (2016). Many studies have greatly outlined the plant’s ability to improve both short-term and long-term memory, and the cerebral circulation boost has a lot to do with the efficacy of such benefits (Balch, 2010).  Some studies indicate an improvement to the peripheral circulation system, also promoting brain function and memory (2010). These same studies have backed up claims that Ginkgo can enhance concentration (2016).   One holistic encyclopedia even suggests the herb can protect the brain (Murray & Pizzorno, 1998)


Ginkgo is known for its potent antioxidant effects, especially within the brain, cardiovascular system, and retina (Balch, 2010).  The impressive flavonoid content within the plant boasts powerful longevity effects (Murray & Pizzorno, 1998).  Due to these outstanding benefits to the body, the plant has been considered throughout Chinese holistic healing history as an anti-aging herb. They also respected the plant for its ability to improve the body’s resistance to the environment (1998).  The antioxidant properties of Ginkgo Biloba are one of the reasons the herb is so popularly prescribed around the globe in the medicinal world (Beshara & Haynes, 2019). The potent antioxidant effects are also one of the reasons Ginkgo offers such positive effects in terms of improve cognitive function (Kaur et al., 2018).



Ginkgo possesses amazing anti-inflammatory properties, even being able to reduce inflammation where there is nerve tissue damage (Chevallier, 2016). This has especially proven helpful for multiple sclerosis patients.  And that makes sense, since the plant provides enhanced blood flow to the central nervous system.  It has even been suggested to strengthen and support nerve tissue (2016). Chinese medicine has long turned to Ginkgo for the anti-inflammatory effects its fruit and seed possess, often referring to it as a tonic for the body (Orr, 2014). Many recent studies are showing Ginkgo to have the ability to significantly decrease oxidative stress and reduce neuroinflammation (Kaur et al., 2018).

Circulatory Issues

Ginkgo is well known for its ability to enhance circulation with numerous published empirical studies, even in the Journal of the American Medical Association (Balch, 2010). The leaves of the Ginkgo plant produce some of the plant’s most potent medicinal properties for improving circulation and blood flow (Chevallier, 2016). The Ginkgo leaves are usually extracted to make a strong tincture, liquid extract, or pill/tablet. And as previously mentioned, these extracts have especially been useful in improving cerebral circulation.  The plant’s ability to inhibit the platelet activating factor (PAF), reduces the likelihood of a blood clot and stroke (2016).

Ginkgo Biloba is also a purported, natural treatment for erectile dysfunction.  One study revealed that participants were experiencing more erections (Murray & Pizzorno, 1998). In fact, the erections were not just more frequent, but also improved in quality and duration.  This is probably due to the herb’s ability to improve circulation and blood flow.  Other studies revealed the plant’s ability to offset sexual dysfunction caused as a side effect of antidepressant drugs (1998). It is also worth noting that the plant is great at improving blood flow to the lower region of the body (Conkling & Wong, 2006).

Dementia, Alzheimer’s Disease, and Many Neurological Conditions

Truly, the jury is still out on how effective Ginkgo Biloba may be as a treatment for Alzheimer’s and Dementia, however, there are many clinical studies which have found a variety of positive benefits (Chevallier, 2016).  Even this smaller collection of empirical data promoting the benefits of the natural herb for those suffering from neurological or brain-related conditions is encouraging.  As previously mentioned, the herb’s ability to improve memory (2016) is most certainly useful for those suffering from memory loss due to age or a neurodegenerative condition.  One recent study proved its substantial benefit to dementia patients (Balch, 2016).  And the plant is even shown to slow the progression of Alzheimer’s disease altogether (2016).

As previously mentioned, Ginkgo Biloba can provide significant benefits to patients suffering from multiple sclerosis (Murray & Pizzorno, 1998).  The herb has been empirically proven to improve cognitive impairment and overall mental function in MS patients.  It is able to improve attention, executive function, and memory performance (1998).  There are even studies which purport that the herb has a positive effect on anxiety (Beshara & Haynes, 2019).

Other Benefits

The seeds of the Ginkgo plant are commonly prescribed by Chinese medical professionals for issues with the urinary tract or the bladder (Chevallier, 2016). They are also brilliant for reducing wheezing and treating a general cough, although it is important to remember to remove the husk of the seed first, which only contains toxins and none of the plant’s useful constituents. The seeds also help reduce excess phlegm, treat vaginal discharge, and improve incontinence (as well as other bladder issues) (2016).  In Ayurvedic practice, the herb was traditionally used to manage cholesterol (Orr, 2014).

There is a lot of research which indicates Ginkgo Biloba can be used to treat depression and with great efficacy (Chevallier, 2016). It has especially good antidepression effects on individuals over the age of 50, or patients who suffer from cerebrovascular insufficiency (Murray & Pizzorno, 1998). Recent studies have outlined the plant’s great ability to aide recovering stroke patients (Balch, 2010).  It has also been used to treat hearing problems, macular degeneration, and impotence (2010).  It is reasonable to argue that the Ginkgo plant is one of the most diverse holistic herbs on the planet.

Dosing and Usage Information

Although there are many ways to prepare the Ginkgo plant, a tincture or tablet is one of the most common methods for consumption.  There are many high quality Ginkgo biloba extracts sold as dietary supplements, which usually suggest a dose of around 120 to 300 mg per daily pill.  This is also the dosage noted as safe in most holistic resources (Beshara & Haynes, 2019). 

It is worth noting that there are differences between preparation methods in terms of effects.  The traditional preparation method of a tincture extract (using the leaves only), is the best administration method when using Ginkgo for poor circulation, blood-related issues, or asthma (Chevallier, 2016).  Liquid decoctions of the seeds are the best way to use Ginkgo for wheezing, or treating a cough (2016).  The capsule/tablet method (usually consumed as a dietary supplement) is best for memory loss and most of the other benefits the Ginkgo plant offers (2016).

A standardized extract of Ginkgo Biloba is normally  24 percent flavoglycosides and 6 percent terpene lactones (Conkling & Wong, 2006).

Side Effects

Although the plant does have the potential to create some unpleasant side effects, they are minimal and rare.  Some of the side effects which have been reported in some studies include headaches, dizziness, upset stomach, constipation, tachycardia (fast heartbeat), and allergic skin reactions (Conkling & Wong, 2006).

Other Important Information


It is important to note that Ginkgo Biloba can create issues for persons taking anticoagulants (blood-thinning medication) or those who regularly take over-the-counter pain medication (Conkling & Wong, 2006).  Although anyone who is considering adding a dietary supplement to their daily regimen should consult a physician beforehand, it is especially important for individuals on anticoagulants or OTC pain medicine to discuss Ginkgo with their doctors.  It should also not be used by anyone who is about to undergo surgery or a dental procedure.


The Ginkgo plant is an extremely versatile herb, possessing the ability to improve seemingly endless conditions and ailments. The studies, empirical data, clinical trials, and other research have shown the plant to offer incredible benefits with almost no side effects.  The side effects which do exist are minimal, trivial to say the least. In terms of treating neurological, neurodegenerative, or circulation issues, the plant is unbelievable and well-revered across the globe. Ginkgo is one of the most popular nootropic herbs for improving mental response times and memory, and maximizing learning potential (Orr, 2014).  To summarize, Ginkgo Biloba is a powerful and capable nootropic worthy of a place in nearly any nootropic stack.

A Note from NooFiles

This article is intended to be used for information only.  We want to remind you that consulting your physician is recommended before adding any dietary supplement of any kind to your daily regimen.


Balch, P. (2010). Prescription for Nutritional Healing. Fifth Edition. Avery Publishing. New York, New York. ISBN 978-1-58333-400-3

Beshara, J., Engle, D., and Haynes, K. (2019). Beyond Coffee. Monocle Publishing. ISBN 9781544505459

Chevallier, A. (2016). Encyclopedia of Herbal Medicine. Third Edition. DK Publishing. New York, New York. ISBN 978-1-4654-4981-8

Conkling, W. and Wong, D. (2006). The Complete Guide to Vitamins and Supplements: The Holistic Path to Good Health. Avon Health Publishing. New York, NY. ISBN: 978-0-06-076066-3.

Kaur, S., Sharma, N., Nehru, B. (2018). Anti-inflammatory effects of Ginkgo biloba extract against trimethyltin-induced hippocampal neuronal injury. Inflammopharmacology. Vol. 26(1). Pp. 87-104. DOI: 10.1007/s10787-017-0396-2

Murray, M., and Pizzorno, J., (1998). The Encyclopedia of Natural Medicine. Third Edition. Atria Paperback. ISBN 978-1-4516-6300-6

Orr, S. (2014). The New American Herbal. Clarkson Potter Publishers. New York, New York. ISBN 978-0-449-81993-7

Roland, P. and Nergård, C. (2012). Ginkgo biloba–effekt, bivirkninger og interaksjoner [Ginkgo biloba–effect, adverse events and drug interaction]. Tidsskr Nor Laegeforen. Vol. 132(8). Pp. 956-9. Norwegian. DOI: 10.4045/tidsskr.11.0780