L-theanine, known simply as theanine, is an amino acid that’s commonly found in tea leaves. Theanine is regarded as a nootropic and an adaptogen as it protects memory and cognition while relieving stress and anxiety. Unlike most prescription anti-anxiety pills, theanines helps you relax without inducing drowsiness.
It is naturally found in black and green tea, as well as, Bolete mushrooms. But how much tea can you really drink in a day? Since this amino acid is not available in the more commonly eaten foods, its beneficial to take L-theanine supplements. It’s easily available online and in health stores in the form of capsules or tablets.
If you are looking for a ‘smart drug’ that helps you ease stress and unwind, try out L-theanine as this drug also helps improve your attention span and focus, helping you become more productive in life.
L-Theanine: Mechanism of Action
L-theanine is also called r-glutamylethylamide. Unlike the more commonly known amino acids such as leucine, tryptophan, lysine, or methionine that form proteins in our body, L-theanine plays a unique role.
Theanine has been found to influence nerve impulses in the brain and has an impact on the release of neurotransmitters such as Gamma-aminobutyric acid (GABA). With its anxiolytic effect, L-theanine is effective in the treatment of hyperactivity and sleep-related issues.
L-theanine is structurally similar to the amino acid glutamine. Though both these amino acids support energy levels and mental health, theanine is more effective as a natural stress reliever. Glutamine plays an important role in the production of glutamate, an excitatory neurotransmitter in the brain. High levels of glutamine cause anxiety, restlessness and ADHD-like symptoms, such as inability to focus.
Since L-theanine binds to the same receptors in the brain as glutamate, it displays inhibitory effects. GABA is the primary inhibitory neurotransmitter that counterbalances the action of glutamate.
Other than its anxiolytic properties, L-theanine offers many health benefits. Various studies have found evidence that theanine helps support the cardiovascular system, protects the brain and helps relieve symptoms of mental disorders such as dementia, Schizophrenia and Alzheimer’s disease. It may help prevent and treat cognitive loss.
Stroke patients may benefit from L-theanine supplementation. If you are suffering from mood related disorders, insomnia, or has trouble falling asleep, L-theanine should definitely be on your list. Theanine is also useful for treating high blood pressure and Post-traumatic stress disorder (PTSD).
5 Health Benefits of L-theanine
With so many L-theanine health claims that seem too good to be true, let’s take a closer look at the ones that have been scientifically proven.
L-theanine Relieves Depression
This is one claim that has substantial scientific evidence to support it. L-theanine. There have been numerous studies to evaluate L-theanine’s ability to promote relaxation without causing sedation. Anti-anxiety pills often leave you feeling lethargic and tired. Though L-theanine may not prove much useful for severe anxiety, it can help calm you down when you feel depressed, mildly anxious or nervous without leaving you feeling tired.
In a 2017 an open-label clinical trial from the National Center of Neurology and Psychiatry, Tokyo, Japan, evaluated whether L-theanine is effective for patients with major depressive disorder (MDD). 20 patients with MDD were administered 250 mg of L-theanine per day for 8 weeks. The study concluded that:
“L-theanine administration is safe and has multiple beneficial effects on depressive symptoms, anxiety, sleep disturbance and cognitive impairments in patients with MDD.”
Alpha brain waves are associated with our state of arousal, mental alertness and wakeful relaxation. Researchers from the Unilever Food and Health Research Institute, in the Netherlands, studied the effects of L-theanine on brain waves at specific periods after consuming 50 milligrams of L-theanine. relative to placebo, they found that there was a greater increase in alpha activity across time in the L-theanine condition. The study concluded that:
“L-theanine, at realistic dietary levels, has a significant effect on the general state of mental alertness or arousal. “
L-theanine Relieves Anxiety
Since L-theanine’s has anti-stress effects comes from its ability to inhibit cortical neuron excitation, it has to first get across the blood brain barrier. When given as an injection, L-theanine is able to easily cross the blood-brain barrier than when taken orally.
Oral supplements are not so quick acting, but they are effective and they raise up brain concentrations of the compound for up to 5 hours. Theanine mostly impacts two important areas of the brain namely, the amygdala and hippocampus. These are the parts of the brain that help control fear responses and memory.
A 2016 study from the Swinburne University of Technology, Hawthorn, Australia investigated the effects of L-theanine on mood responses to a cognitive stressor. The double-blind, placebo-controlled, study used 34 healthy adults aged 18 to 40. They were given a nutrient beverage containing 200 mg of L-theanine. The researchers recorded that:
“Subjective stress response to a cognitive stressor was found to be significantly reduced one hour post-dose, and cortisol response was significantly reduced three hours post-dose”
As tea contains both L-theanine and caffeine, researchers from the School of Food and Nutritional Sciences, University of Shizuoka, Japan, compared the effects of both on mental task performance and physiological activities. 14 participants were tasked under conditions of physical or psychological stress, over three separate trials, in which they were given L-theanine + placebo, caffeine + placebo, or placebo only.
L-theanine significantly inhibited the blood-pressure increases caused by the mental tasks in the high-response group while Caffeine had a similar but smaller inhibition of the same. As compared with placebo intake, L-theanine also reduced the Tension-Anxiety scores.
Fight Insomnia and Improve Sleep with L-Theanine
Many people suffer from insomnia. Whether its an exam, a date, a client meeting or a project deadline, we all have a tendency to spend sleepless nights, tossing and turning in bed, worrying about the major or minor issues in our lives. L-theanine supplements are great for improving your sleep, if your anxiety or sleep issues are not too severe. But if your mind is simply too hyperactive, as with ADHD, L-theanine can have a positive impact.
L-theanine was also found to counter the effects of stimulants such as coffee and its calming effect reduces wakefulness and jitters, enabling you to fall asleep much faster.
L-theanine is often given along with Melatonin to induce sleep. 100–200 milligrams of L-theanine can be taken with about 3 grams of melatonin, at bedtime, to reduce stress and promote sleep. But keep in mind that high doses of L-theanine can have the opposite effect.
A 2011 study from the University of British Columbia, Canada, evaluated the efficacy and safety of L-theanine as an aid improve sleep quality in children with ADHD. 98 boys, ages 8-12 years, formally diagnosed with attention-deficit/hyperactivity disorder (ADHD), were given tablets containing L-theanine, twice a day. The study conducted over a six week period concluded that:
“400 mg daily of L-theanine is safe and effective in improving some aspects of sleep quality in boys diagnosed with ADHD.”
L-Theanine Can Help Improve Attention
The combination of L-theanine and caffeine has been found to improve cognition, attention and alertness. Caffeine and L-theanine seem to share a synergistic relationship that surprisingly improves focus and concentration without inducing that ‘wired’ or jittery feelings. 200 mg each of L-theanine and caffeine is recommended for this purpose.
A 2017 study conducted by researchers from the Department of Nutritional Sciences, Texas Tech University, USA and from the University of Peradeniya, Sri Lanka, investigated “whether theanine and theanine-caffeine combination have acute positive effects on cognitive and neurophysiological measures of attention.
They used 20 male volunteers, to compare the effects of 200 mg l-theanine, 160 mg caffeine, their combination, one cup black tea and distilled water as a placebo on cognitive and recognition visual reaction time and neurophysiological measures of attention. The study concluded that:
“A dose of theanine equivalent of eight cups of back tea improves cognitive and neurophysiological measures of selective attention, to a degree that is comparable with that of caffeine. Theanine and caffeine seem to have additive effects on attention in high doses.”
L-Theanine Helps Protect Memory
L-theanine seems to have many benefits that impact our physical and mental health. It is believed to have neuroprotective effects that enhance brain functions. In a 2016 study from the Faculty of Health, University of Canberra, Australia, the researchers examine the potential benefits of L-theanine in relation to human health.
In a 2011 Korean study, when a combination called LGNC-07 (360 milligrams of green tea extract along with 60 milligrams of theanine) was administered to patients with mild cognitive impairment, 3 times a day for a period of 16 weeks, the researchers observed that the L-theanine combo improved recognition skills without negatively affecting verbal and visuospatial memory.
After 3 hours, they noted a significant increase in brain theta waves, in the temporal, frontal, parietal, and occipital areas, in the eye-open and reading states. Brain theta waves are indicators of cognitive alertness. The study concluded that LGNC-07 (L-theanine ) has potential as an intervention for cognitive improvement.
Neurons get damaged and killed by the overactivations of receptors for the excitatory neurotransmitter glutamate. This is called excitotoxicity and is believed to be linked to neurodegenerative disorders, stroke and schizophrenia. The neuroprotective benefits of L-theanine may be due to its ability to prevent excitotoxicity or the excessive glutamate stimulation of brain cells. L-theanine thus offers neuroprotection for the aging brain by blocking some of glutamate’s effects.
L-Theanine For Heart Health
There is a lot of scientific evidence supporting the fact that green tea reduces inflammation and heart health. Active compounds like green tea catechins or theaflavins in green tea were given credit for providing these benefits, but there is increasing evidence that the L-theanine content of green tea plays a major role in its cardiovascular benefits.
If you experience increased blood pressure in stressful situations, then L-theanine supplementation may be beneficial for you. Theanine is believed to help regulate nitric oxide and thus help prevent blood pressure spikes that occur in response to such stressful events.
Nitric acid is produced by our body and it plays many roles, but its most important function is vasodilation. It relaxes the inner muscles of the blood vessels, making them become wider and thus it helps increase blood circulation while reducing blood pressure. Adequate levels of nitric oxide provide protection against artery-blocking clots.
A 2012 study from the Laboratory of Nutritional Biochemistry, School of Food and Nutritional Sciences, University of Shizuoka, Japan found that L-theanine significantly inhibited the blood-pressure in high stress response individuals making it evident that L-theanine does offer cardiovascular benefits.
L-Theanine Reduces Stroke Impact
Considering its cardiovascular benefits, it’s evident that L-theanine is indeed beneficial for those suffering from health problems. Prevention is always better than cure, but if a stroke did occur, then it is most important to minimize the damage being caused and protect the brain cells from irreversible damage. Research has found evidence that administration of L-theanine within 12 hours of the stroke can help protect brain cells from damage caused by the stroke. This protective effect may kick in for a period of up to 24 hours of the stroke.
A 2013 study from the Department of Pathophysiology, I. P. Pavlov Federal Medical University, St-Petersburg, Russian Federation, investigated the neuroprotective effect of L-theanine in the rat model of stroke. L-theanine was administered at 3, 12, and 24 h after the stroke. The researchers concluded that:
“L-theanine at reperfusion exerts neuroprotective effect in the in vivo rat model of stroke. Local treatment with L-theanine at reperfusion prevents glutamate receptor agonist-mediated brain injury.”
When a stroke occurs, there is inadequate blood flow to the brain thus reducing brain oxygen levels. Reperfusion injury, or reoxygenation injury, is the tissue damage caused when blood supply returns to tissue after a period of lack of oxygen. It is important to administer L-theanine before this tissue damage occurs.
Side Effects and Risks of L-Theanine
It is considered safe to consume L-theanine supplements or teas with L-theanine as there are no direct side effects to taking this amino acid. In general, consumption of large quantities of green tea may result in nausea, irritability, and stomach upsets, not because of the L-theanine content, but due to the caffeine content.
Though L-theanine does exhibit some anti-tumor properties, consuming too much tea can prove harmful for those suffering from cancer, as some other compounds in teas may aggravate cancers. The Memorial Sloan Kettering Cancer Center reported that certain compounds in green tea such as polyphenol EGCG were found to reduce the effectiveness of chemotherapy drugs such as bortezomib. So chemotherapy patients are advised to consult with their physicians before taking L-theanine supplements or drinking too much tea, coffee or other caffeinated drinks.
Another general warning is for pregnant women and children. The effect of L-theanine on pregnant women has not been studied much, so it is safer for women in such conditions to avoid taking this supplement. It is better they limit their tea intake too to avoid getting over- caffeinated.
L-Theanine Dosage Recommendations
The Japanese are famous for their tea ceremonies and tea seems to hold a sacred place in their hearts. For centuries, they have attributed many aspects of their health and well being to their ancient practice of drinking tea, especially green tea.
Drinking tea is generally considered safe and there are no reported incidences of an L-theanine overdose. But this does not mean you can take it in copious amounts. Moderation is key to all things in life and most nootropics and adaptogens have been found to be more effective in lower doses than very high doses.
L-theanine supplements are commonly available in 200-mg tablets. Though recommended dosages per day range from 200 to 400 mg per day, it is always best to consult your physician to make sure which dosage suits your requirements the best. Dosages as high as 4000 mg/kg of body weight per day appeared to be safe in animal studies as no adverse effects were noted by the researchers, in a 2006 study from the
Department of Pharmacology and Toxicology, Medical College of Virginia, in the USA.
The Final Note
L-theanine is an amino acid that occurs naturally in teas, both green and black. Since it is not practical or safe to drink unlimited amounts of caffeinated beverages like tea, it’s advisable to take L-theanine supplements to reap its innumerable health benefits. The L-theanine content of tea is believed to be responsible for many of these health benefits.
After a stressful day, many people love to have a cup of tea and relax, sipping it slowly. This act seems to provide that wakeful relaxation similar to that experienced during and after meditation. The L-theanine content in tea promotes alpha-wave brain production which helps you relax completely, yet remain alert and ready for your next task.
L-theanine offers a wide range of health benefits though its most often sought after for its abilities to improve mental focus and promote better sleep quality. Though L-theanine supplements are considered safe for consumption, more research is needed to confirm many of its claims. Studies, both human and animal models, have already proven that L-theanine does help with relaxation, neuroprotection and improved sleep.
Anju Mobin is a certified nutritionist who writes health and wellness articles online. The holder of two graduate degrees, she combines her passion for advertising with her knowledge of the health industry to create custom content for healthcare products. She is the founder and editor of the health website fitnesshacks.org. Find out more about her from her LinkedIn profile or contact her at firstname.lastname@example.org.