L-Theanine: Health Benefits, Dosage and Precautions

 

Author

Dr. Ayesha Tufail

Our Certified Medical Doctor, Researcher and Top-Rated Medical Writer on Upwork. Dr. Ayesha Tufail has more than 10 years of experience working as a General Practitioner. Her areas of research include Stem Cell Therapy, Herbal Health Supplements & Adult ADHD.

You can get in touch with Dr. Ayesha via her LinkedIn account linked at the end of this page.
 

What is L-Theanine?

L-theanine is a natural amino acid that is primarily found in tea leaves, especially in green tea. It is also found in small amounts in varieties of mushrooms. L-theanine is unique in that it is not commonly found in many foods. However, it can be consumed in the form of L-theanine supplements, which are widely available in health stores. L-theanine supplements are generally safe and well-tolerated, making them a convenient and effective way to support your mental health and well-being.

 

Discovery of L-Theanine

L-theanine was discovered by a Japanese Scientist in 1940 when he was studying the composition of green tea. Dr. Hattori discovered that a unique amino acid was present in the leaves of Camellia sinensis, the plant used to produce green tea. This amino acid was later identified as L-theanine. It is a very popular ingredient in functional foods and beverages in Japan as well as in dietary supplements designed to produce mental and physical relaxation, without inducing drowsiness.

 

Health Benefits of L-Theanine

L-theanine can cross the blood-brain barrier and is thought to work by affecting multiple neurotransmitters like GABA, serotonin and dopamine in the brain to promote relaxation, reduce stress, anxiety and improve cognitive function. Here are some of the key benefits you can expect from taking L-theanine supplements:

1. Stress and Anxiety Reduction 

L-theanine has been shown to promote relaxation and reduce stress and anxiety levels without causing drowsiness. It does this by increasing levels of GABA (gamma-aminobutyric acid), a neurotransmitter that helps regulate mood and promotes feelings of calmness.

2. Improved Focus and Concentration

Studies have demonstrated that L-theanine improves cognitive function, including attention and focus. It does this by increasing alpha brain wave activity, which is associated with a state of relaxed wakefulness and improved attention.

3. Improved Sleep Quality

Research has demonstrated that L-theanine promotes better sleep quality by increasing the amount of restorative REM sleep and reducing the amount of time it takes to fall asleep. It does this by increasing levels of serotonin and dopamine, two neurotransmitters that play a role in regulating sleep.

4. Potential Cardiovascular Health Benefits

Studies suggest that L-theanine may support cardiovascular health by reducing blood pressure and improving blood flow. It does this by increasing levels of nitric oxide, a molecule that can relax blood vessels and improve circulation.

5. Antioxidant Properties

L-theanine has antioxidant properties, meaning it helps protect cells from damage caused by free radicals. This may help reduce the risk of chronic diseases such as heart disease, cancer and Alzheimer's disease.

 

Current & Future Implications of L-Theanine

The current and future implications of L-theanine are promising, as it has shown potential in a wide range of applications, including mental health, cognitive function, and physical performance. Here are a few examples:

1. Role of L-Theanine in ADHD

L-theanine has been studied for its potential use in ADHD (Attention Deficit Hyperactivity Disorder) as a natural alternative to prescription medications. Researches suggest that it may improve cognitive function, reduce anxiety and hyperactivity, promote better sleep quality and potentially allow for a lower dosage of medication to be used in ADHD. Overall, while more research is needed to fully understand the potential benefits of L-theanine for individuals with ADHD, it appears to offer some promising benefits.

2. Role of L-Theanine in enhancing athletic performance

L-theanine is a popular supplement used by athletes to support mental and physical performance. It can help improve focus and concentration, reduce stress and anxiety, enhance endurance, promote better sleep quality and potentially reduce muscle damage caused by intense exercise.

Studies suggest that L-theanine may enhance endurance during physical activity by increasing levels of nitric oxide, a molecule that helps improve blood flow and oxygen delivery to muscles. L-theanine may also help reduce muscle damage caused by intense exercise by reducing oxidative stress and inflammation.

3. Role of L-Theanine in Schizophrenia

Schizophrenia is a complex and severe mental disorder that can be challenging to treat. While there is limited research on the effects of L-theanine on schizophrenia, some studies have explored its potential role in the treatment of this disorder. L-theanine has been shown to have anxiolytic effects and improve cognition in schizophrenia. Some studies suggest that L-theanine may have antipsychotic effects, meaning it could help reduce symptoms such as delusions and hallucinations in schizophrenia. However, the evidence is limited and more research is needed to fully understand it.

4. Role of L-Theanine in Cancer

There has been some research on the potential role of L-theanine in cancer prevention and treatment, but the evidence is still limited and further research is needed to fully understand its effects. Here's what we know so far:

• L-theanine has antioxidant properties, which means it can help protect cells from damage caused by free radicals. By protecting cells from free radical damage, L-theanine may help reduce the risk of developing cancer.
•  L-theanine has been shown to support the immune system by promoting the production of immune cells and enhancing their activity. A healthy immune system is important for fighting off cancer cells and preventing cancer from developing.
• Some studies suggest that L-theanine may enhance the effects of chemotherapy drugs by increasing their absorption and reducing their toxicity. This could potentially improve the effectiveness of chemotherapy treatments and reduce side effects.

5. Role of L-Theanine in Liver disease

Liver inflammation, also known as hepatitis, can result from various causes such as viruses, alcohol or autoimmune diseases. Research suggests that L-theanine may have potential benefits in reducing liver inflammation.

L-theanine has anti-inflammatory and antioxidant properties which help in reducing inflammation in the liver. Studies have shown that L-theanine may help reduce liver injury caused by factors such as alcohol or toxins. This suggests that L-theanine may have potential benefits in treating liver inflammation and preventing further liver damage.

While these findings are promising, it's important to note that the research on L-theanine and liver inflammation is still limited and more studies are needed to fully understand its effects.

6. Role of L-Theanine in Reducing Weight

L-theanine is not typically used as a weight loss supplement, some research suggests that it may have a role to play in promoting weight loss indirectly when used as a part of healthy weight management.

L-theanine may help in reducing food cravings and promoting satiety. Some research suggests that L-theanine may increase levels of certain hormones, like leptin and adiponectin, which are involved in regulating appetite and metabolism. By promoting feelings of fullness and reducing cravings for unhealthy foods, L-theanine may help to support healthy eating habits and weight management. Studies also suggest that L-theanine may promote weight loss by improving sleep quality and by reducing stress and anxiety.

7. L-theanine and Caffeine

Research has shown that L-theanine and caffeine work together synergistically to improve cognitive performance and reduce mental fatigue. One study found that a combination of L-theanine and caffeine improved accuracy and alertness during a cognitive task compared to caffeine alone. Another study found that a combination of L-theanine and caffeine improved subjective alertness and reduced mental fatigue compared to placebo.

 

How to Take L-Theanine Supplements

To get the most benefits from L-theanine supplements, it's important to take them correctly. Below are some tips for taking L-theanine supplements.

It's best to start with a low dose and gradually increase it as needed. Most supplements contain between 100-200 mg of L-theanine and taking it with food can help increase absorption and effectiveness.

L-theanine supplements are most effective when taken at the right time. Many people find it helpful to take them in the morning or early afternoon to support focus and concentration. L-theanine, when taken at night, helps to promote sound sleep.

When choosing L-theanine supplements, be sure to choose a high-quality product from a reputable brand to ensure safety and effectiveness.

 

Recommended Dose of L-Theanine

The recommended dose of L-theanine can vary depending on the specific product, as well as individual factors such as age, weight and health status. In general, most L-theanine supplements recommend a dose of 100-200 mg per day. As a general guideline it is recommended to take no more than 600 mg within a 6-hour period and no more than 1,200 mg within a 24 hour period.

 

L-Theanine Supplements

The most important source of L-theanine is green tea. Green tea constitutes, on average, only 1-3% of the weight of dry tea leaves. L-theanine is widely used worldwide. Apart from green tea, L-theanine is produced in the form of supplements as well. The following are the two most important supplements of L-theanine.

• Synthetic L-Theanine 

Synthetic L-theanine supplements are prepared in the lab by either chemical synthesis or bacterial fermentation. Synthetic L-theanine is chemically identical to the L-theanine found in green tea leaves and considered safe for consumption.

• Green Tea Extracted L-Theanine 

Green tea extract supplements are also available in the market. These supplements are even more potent than synthetic L-theanine, and they use a highly concentrated form of L-theanine extracted from green tea leaves. They provide the highest concentration of L-theanine per serving, potentially allowing for more potent effects and smaller serving sizes.

 

Synthetic vs Green Tea Supplements

Theanine is chemically a chiral compound with two isomers, L-form and D-form. In natural products, especially in tea, only L-theanine is found whereas in synthetic supplements both isomers have been found to be present. Research suggest that:

1. The L-isomer is a mutual antagonist of the D form
2. The L-form is more stable and potent as compared to the D form
3. The D-form is unstable & readily excreted from the body

So, in comparison L-theanine (from green tea) supplements are more effective as compared to synthetic supplements. Green tea supplements contain not only the 'L' isomer of Theanine but also a small amount of caffeine and other chemicals present in green tea, thus green tea extraction produces more potent effects of L-theanine.

 

Possible Side Effects of L-Theanine

L-theanine is generally considered safe and well-tolerated when taken in appropriate doses. Here are some of the possible side effects of L-theanine:

• Some individuals may experience gastrointestinal discomfort such as nausea, diarrhea, or stomach upset when taking L-theanine.
• In some cases, L-theanine may cause headaches or migraines.
• L-theanine may lower blood pressure levels, which could be a concern for individuals with low blood pressure or those taking medications to lower blood pressure.
• While L-theanine is not known to cause drowsiness, some individuals may experience this side effect at higher doses.
• In rare cases, individuals may experience an allergic reaction to L-theanine, which could include symptoms such as hives, rash, or difficulty breathing.
• It's generally recommended that pregnant or breastfeeding women avoid taking L-theanine supplements, as there is not enough information available to determine their safety.

 

Interaction of L-Theanine with Medication

L-theanine is generally considered safe and well-tolerated, but it's possible that it may interact with certain medications. Some medications that may interact with L-theanine include:

• L-theanine may lower blood pressure, so taking it with medications that lower blood pressure may increase the risk of hypotension.
• L-theanine is sometimes taken with stimulants like caffeine to reduce their negative effects, but it's important to be cautious when combining these substances, as they may interact in unpredictable ways.
• L-theanine may enhance the effects of benzodiazepines, which are commonly used to treat anxiety, so it's important to be cautious when taking these medications together.
• Some research suggests that L-theanine may interact with certain antidepressant medications, so it's important to talk to your healthcare provider if you are taking these medications and are considering taking L-theanine.

 

Final Thoughts

If you're looking for a natural way to reduce stress, improve focus, and support your overall well-being, L-theanine supplements may be just what you need. With its many benefits and few side effects, L-theanine is a safe and effective way to find calm and focus in your busy life. Try it out today and experience the power of L-theanine for yourself!

 

Medical Disclaimer: While we have delve into the research available on the health benefits of these awesome supplements we offer, this is for informative purposes only and shouldn’t be taken as medical advice. Those who have any health-related queries should reach out to a medical professional. These statements have not been evaluated by the Therapeutic Goods Administration. This article is not intended to diagnose, treat, cure, or prevent any disease. 

 

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