L-Theanine Capsules: Benefits, Dosages and Side Effects

What is L-Theanine?

Green tea (Camellia sinensis), black tea and some mushrooms (Boletus badius) contain the amino acid L-theanine. In tea, the element works with caffeine to help stimulate the body without all the jitters and anxiety. If drinking tea is not your thing, then L-theanine capsules are available in supplemental form (x).

L-theanine is the taste of the green tea you drink. The Japanese call the taste umami one of the five primary tastes, savory. The other four are sweet, sour, bitter and salty (x).

The amino acid helps with rapid visual data processing, working with numbers, reverses delayed recognition in reaction time, handles stress, calms the nerves and a better night’s sleep (x). Though it can help you sleep at night, it is not a sedative. L-theanine relaxes the nervous system, giving you a restful, relaxing sleep (x).

L-theanine is a non-protein amino acid related to glutamine, a protein amino acid. Your body does not produce this element, though it is unnecessary for humans. Still, L-theanine offers benefits worth considering for particular aspects of your health (x).

History of L-Theanine

For thousands of years, drinking green tea has brought relaxation and helps with many aliments. Theanine is the substance responsible for the sense of peace. In 1946, Japanese scientists discovered and isolated L-theanine as the cause of all the health benefits related to green tea. In 1964, after thorough studies, Japan approved using L-theanine (x).

Japanese scientists in 1999 confirmed several properties unique to L-theanine. Besides facilitating relaxation, the amino acid also controlled hypertension, improved learning abilities, heightened mental sharpness, boosted concentration, reduced caffeine effects and supported the immune system (x).

Some studies show the umami taste boosts the metabolism, decreasing the risk of obesity. Other studies have confirmed that the amino acid also facilitates the central nervous system and lowers blood pressure (x).

Benefits of L-Theanine

With studies confirming the virtue of taking L-theanine capsules, let’s take a comprehensive look at the potential health benefits of taking the amino acid. But check with your healthcare provider before taking a supplement:

  • Improves mental focus
  • Help relax and sleep
  • Overall relaxation
  • Improved cognitive performance
  • Helps weight loss
  • Heightens immune system
  • Lowers blood pressure
  • Works in tandem with some cancer drugs
  • Supports the central nervous system

Improves Mental Focus and Cognitive Performance

A study performed in 2012 proved that there’s nothing like a good cup of tea in the afternoon to help you finish off a work day. Also, supporting these findings is that tea is, after water, the most consumed drink in the world (x).

Researchers discovered that those who take 100 mg of L-theanine performed better at attention tasks, making fewer errors. The same study showed that drinking 50 mg of caffeine or combining caffeine and L-theanine helped improve the ability to focus (x).

Another study examined the potential effects of administering L-theanine for four weeks, targeting cognitive functions and stress-related symptoms. Thirty healthy adults participated in the trial. Each one took either 200 mg of the amino acid or placebo tablets. The outcome determined that L-theanine can support mental health in the general population. Particularly those with cognitive impairments and stress-related conditions (x).

Other reports support taking the amino acid to help improve an individual’s sleep quality. Also, a favorable report supports administrating 250 mg L-theanine in patients with substantial mental disorders for potential therapeutic effects (x).

L-theanine appears to help patients with Parkinson’s because the amino acid helps the body take in polyphenols. Polyphenols protect your body against oxidative stress as an antioxidant (x). The amino acid is an antioxidant as well (x).

A study showed that L-theanine reduced the risk of Parkinson’s disease because of its neuroprotective effects and positive influence on the central nervous system (x).

In an article by Andrea Purcell, ND, she writes about patients describing “nervousness, irritability, edginess, heart palpitations, difficulty breathing, hurriedness, and inability to turn off the mental motor. These are just a few descriptions that I hear daily in private practice. Stress is present, people become overwhelmed by it and then get stuck in an anxiety cycle that leads to sleeplessness and becomes very difficult to get out of.”

Dr. Purcell recommends several natural and healthy solutions for handling stress. One of those solutions is L-theanine capsules, 200 mg, one to two times a day will help take the edge off. Dr. Purcell also recommends consulting with an integrative doctor who looks at the whole body to help with any existing health concern.

Help With Overall Relaxation and Sleep

In the US, millions of adults have difficulty sleeping through the night. They feel dissatisfied and wonder whether using natural sleep or over-the-counter aids can help them get a good night’s sleep. For centuries, the Japanese have sipped green tea to help relax their bodies and sleep. So, it’s only natural that L-theanine capsules can help you sleep through the night (x).

The University of Pittsburgh showed that alterations in sleep patterns begin during middle age. A study performed with 110 volunteers from 20 to 59 years reported that sleep quality changed significantly between the mid-20s and the mid-50s. Participants go to sleep but wake up earlier than expected. They slept less, woke up more frequently during the night, and had fewer deep sleep phases (x). Research supports taking this amino acid because L-theanine helps promote relaxation. The supplement calms the central nervous system, allowing the body to relax and sleep.

Animal studies found that the amino acid prevents glutamate from binding to cells in the brain’s nerves. Thus, this may slow brain activity, promote a more relaxed feeling to sleep and lessen anxiety (x).

Another theory suggests that L-theanine supports the sleep pattern with 50 to 200 mg capsules. People feel drowsy and relaxed, enabling them to fall asleep faster (x). The positive aspect is that this amino acid is a natural solution, helping people avoid taking pharmaceutical drugs. Drugs that are harmful to the body and reduce the quality of life.

Most integrative doctors recommend staying away from sleep medications. These drugs knock a person out, and they wake up in the morning with a hangover. L-theanine seems to help relax the body, promoting a sense of calm so that you can go to sleep without the dreadful side effects of drugs (x).

Helps With Weight Loss

Look at some popular diet supplements and you’ll notice they include L-theanine as one of their ingredients. It’s not because the amino acid burns fat. L-theanine is in weight loss supplements because it helps prevent food cravings, and dieting can cause stress. People under stress crave sweets, like chocolate and ice cream.

Since L-theanine helps calm and relax the body, it makes sense to take the capsules as a natural aid to losing weight. Also, getting enough sleep helps with the weight loss program, which the amino acid helps with as well.

Another aspect of L-theanine in tea is that it contains caffeine, which boosts your mind and body during your workouts to help with losing weight — smart caffeine. The amino acid can enable you to focus more while exercising to achieve the most out of your workouts (x).

In fact, if you are on a calorie-controlled diet, you might need to replace sugary snacks with a snack bar that contains green tea or a warm-up with a cup of tea. The umami flavor can help reduce or suppress your appetite, according to The American Journal of Clinical Nutrition (x).

In fact, according to the Journal of Functional Foods, L-theanine not only helps with diabetes, hypertension and cardiovascular disease but also assists in the reduction of obesity (x).

Heightens Immune System

With potential anti-inflammatory qualities, L-theanine helps boost your body’s immune system. That way, the body can fight off illness and make it less likely to get a common cold or the flu (x).

A study using animal models tested the results of using L-theanine to boost the immune system of rats. The findings were positive, showing that L-theanine improved immune responses in young and old mice (x).

Another study involved 20 members of the Polish Rowing team. Athletes tend to get over training syndrome (OTS), which contributes to illness and decreased performance. OTS causes inflammation in the body and can cause immune impairment.

Randomly, ten members took 150 mg of L-theanine for six weeks, while the other ten took a placebo. The subjects rowed on an ergometer, going 2000 meters. Researchers took blood samples one minute after testing and after a 24-hour recovery time.

The results of the extensive study showed that the rowers who took the supplement suggested that L-theanine may positively influence the immune system of athletes (x).

More evidence recommends that L-theanine can help strengthen your body’s ability to fight diseases. The supplement may enhance the immune system because of its metabolite quality. It activates an immune system in the body called gamma-delta T cell. When combined with the amino acid L-cystine, the immune system becomes more stronger to prevent the flu (x).

A study reported combining L-cystine and L-theanine at 490 mg when taken twice a day prevents the common cold (x).

Although these are very positive findings, before starting any new supplement, talk to your healthcare provider first.

Lowers Blood Pressure

High blood pressure, also known as hypertension, is closely related to cardiovascular disease. Studies show that taking L-theanine can reduce blood pressure significantly in spontaneously hypertensive rats. Another critical factor is that the amino acid’s inhibitory influence on caffeine can prevent the cause of blood pressure upsurge (x).

Studies also show that L-theanine can help prevent a specific stroke caused from an injury by widening the arteries (x).

Researchers ran a trial where healthy adults received either 200 mg L-theanine, 250 mg caffeine, both or neither. The adults completed ratings check for anxiety, mood, and alertness with their blood pressure measured. The ratings happened before and 40 minutes after the consumption of the supplements.

The study concluded that physiologically and mentally, L-theanine is beneficial for lowering high blood pressure (x).

A similar study on 16 adults had them perform tasks lasting five minutes and ten minutes. The trial ran for seven days, concluding that L-theanine lowers blood pressure in high-stressed-response adults and reduces anxiety (x).

Works in Tandem With Some Cancer Drugs

L-theanine holds many health benefits, including its involvement in the treatment and prevention of cancer.

L-theanine may help prevent certain cancers, according to the Society of Chemical Industry (x). Animal studies support using forms of L-theanine as therapeutic or auxiliary applications in treating lung and other cancers (x).

An extensive report about the positive effects of L-theanine in treating different health concerns supports the amino acid as a cancer preventative. L-theanine used with anticancer drugs helped decrease the size of tumors (x).

Another study reports the amino acid increased the concentration of the cancer drug in the tumor cells threefold. Likewise, a study shows that L-theanine can protect normal cells from the chemotherapy drug doxorubicin’s adverse effects (x).

Still, another showed that L-theanine treatment caused cell death in four cancer cell lines: colon, breast, hepatoma (liver) and prostrate. The amino acid also enhances the components in the body that play a positive role in tumor cells, supporting cancer prevention. Again, a study proved that L-theanine inhibited in vivo and ex vivo growth of human lung cancer cells and leukemia cell lines (x).

Other Health Benefits

Some other noticeable benefits when taking L-theanine are worth mentioning and watching for future health advances. Research has substantiated positive effects for the liver, gastric ulcers and human embryonic stem cell support (x).

Where to Buy L-Theanine Capsules?

You can purchase L-Theanine Capsules at BulkSupplements.com. The company is an industry-leading manufacturer and distributor of pure dietary supplements. BulkSupplements.com is not just a consumer brand. It also supplies pure ingredients to other brands that distribute food and other supplement products. All products at BulkSupplements.com are manufactured and tested according to current and proper manufacturing practices.

Are you interested in trying L-Theanine as a dietary capsule supplement for its potential to support your central nervous system, weight loss program, immunity function, metabolic health, cardiovascular health, and cancer prevention? Contact BulkSupplements.com to place an order today.

How to Take L-Theanine Supplements

Ascertaining when to take L-theanine capsules depends on what you want or need from your activities or workout. You and your doctor determine what works best for you with the help of a nutritionist.

L-Theanine Dosage

There is about one to two percent of L-theanine by dry weight of green tea leaves. Likewise, you can get approximately 25 to 60 mg of L-theanine in a cup of tea. Fifty mg of L-theanine a day produces noticeable mental alertness. However, if you need a more precise and larger dose, that requires taking capsules instead of tea.

L-theanine capsules average 200 to 500 mg per unit. You’ll have to see how your body adjusts to the different dosages. You can also talk with a healthcare provider and come up with a regiment that suits your needs.

L-Theanine Side Effects

An evaluation of the side effects of L-theanine, adding various dosages to the diet (1500, 3000 and 4000), showed no adverse effects. The Japanese Ministry of Health and Welfare supported L-theanine as a universal food additive in 1964. In the US, L-theanine received the label GRAS (generally recognized as safe) as a non-toxic product (x).

On the other hand, pregnant and nursing mothers should avoid taking supplements.

Those with the following health concerns or situations may want to consult with their health practitioner before implementing L-theanine in the diet:

  • Low blood pressure
  • Children under the age of 18
  • Taking high blood pressure medications
  • Taking prescription or over-the-counter stimulants

The Bottom Line

For thousands of years, the Japanese and Chinese have understood the health benefits of drinking a good cup of tea. It wasn’t until 1946 that the Japanese scientists could isolate what element caused the positive effects of the tea. Since that fruitful day, L-theanine has surprised science with its natural healing powers.

As a westerner, it may not seem very easy to believe that such a panacea can exist on this planet. But it helps many people solve or overcome health concerns that could otherwise make life miserable. Slowly, the West will meet the East and celebrate the benefits of L-theanine ancient healing powers.

Meanwhile, consider taking L-theanine capsules for high blood pressure, cancer prevention and treatment, obesity, cardiovascular disease, alertness, anxiety and a good night’s sleep.

These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.

Author: BulkSupplements Staff