17 Health Benefits Of L-Theanine

L-Theanine is an amino acid analog of the proteinogenic amino acids glutamine and glutamate. It is a well-known constituent of the tea plant (Camellia sinensis). Theanine is also found in fungal sources. It is not made within the human body but could be produced synthetically.

Theanine helps reduce stress and improves one’s mood. It also helps protect the brain and the heart. Theanine often refers to L-theanine as opposed to D-theanine which has fewer benefits.

There is some controversy with respect to supplementing with theanine. As such, its supplement is legal in the USA but not in Europe and other parts of the world. However, L-theanine is generally safe when consumed, especially naturally, in moderation. A typical cup of black tea tends to have 20mg of theanine.

Below are various health benefits of L-Theanine;

1. Helps Deal With Stress

Research has shown that the person who takes L-Theanine has reduced anxiety and stress level. L-Theanine increases alpha wave activity of an individual. This leads to mental relaxation and deep REM sleep. Also, L-Theanine lowers the overall stress hormones, such as cortisol, resulting in relaxation.

2. Provides Protection For Heart And Blood Vessels

L-Theanine increases nitric oxide production in the body which results in improved blood vessel function. Theanine not only enhances blood vessel function, but it also reduces the hardening of the heart arteries by preventing the fat peroxidation of LDL (low-density lipoprotein).

3. For Better Quality Of Sleep

A study has shown that 200mg of L-Theanine before going to bed improves one’s sleep quality. Due to its sedative properties, it affects the serotonin and dopamine level in the body. As compared to other sleeping aids, it provides better quality sleep without the feeling of tiredness. L-Theanine also reduces the time to fall asleep and also helps in getting better sleep.

4. Deals With Schizophrenia

Schizophrenia is a type of disorder that shows its impact on a person’s ability to behave, think or feel clearly. Theanine boosts neurotransmitter production. If you consume 400mg daily, of L-Theanine, for eight weeks, you will notice less severe symptoms of Schizophrenia. Studies have found that amino acid analog can help in protecting the human brain cells from damage and also reduces the toxicity levels in the neural pathways. Ensure you consult your doctor before taking any supplement.

5. Helps With Weight Loss

L-Theanine reduces fatty acids and triglyceride levels in the blood. This helps in the gradual loss of body fat. Psychologically, some people who are upset tend to eat more which impact directly on weight. Theanine reduces the likelihood of getting stressed which means less snacking.

6. Boosts Overall Immunity

L-Theanine boosts overall immunity by stimulating T cells. T cells are those cells which fight against tumors and various infections. Theanine helps in shifting the balance of TH1/TH2 cytokines towards TH1. Theanine also deals with allergic issues by decreasing the production of IgE antibodies and histamine release from the mast cells. If any patient is dealing with severe allergies, in-take of L-theanine can be very useful.

7. Works As An Adjunctive Cancer Treatment

Animal tests have shown that L-Theanine enhances the anti-tumor effects and reduces the toxicity of drugs that are cancer-killing. Also, it deals with microbial infections. Finally, theanine inhibits the growth of lung and liver cells to work as an adjunctive cancer treatment.

8. Beneficial For Liver Injuries

Due to its antioxidant properties, L-Theanine inhibits liver inflammation and decreases the liver oxidative damage, thus, helping to heal liver injuries. Patients who have consumed alcohol a lot in their earlier years and have lost effective use of their liver can take L-Theanine as a rejuvenating supplement for their liver. The patient who does not have a good functioning liver tend to have metabolic problems that can result in serious negative effects on the individual’s health. L-Theanine also helps to reduce bladder hyperactivity problem. That means if someone is dealing with UTI (Urinary Tract Infection), they can take  L-Theanine for relief. L-Theanine’s antioxidant properties also help in fighting microbial infections like the case of UTI.

9. May Heal Stomach Ulcer

L-Theanine stimulates prostaglandin E production and helps alleviate some of the side effects of non-steroidal anti-inflammatory drugs (such as gastric ulcer) due to its antioxidant properties. It also helps to relieve stomach ulcers at a dose of 10mg per kg body weight, but in severe conditions, it requires a dosage of 40mg per kg body weight. Consult your doctor before taking any supplement.

10. Improves Mood

As earlier discussed, L-theanine affects organic chemicals such as serotonin and dopamine in the body. Low serotonin and low Dopamine levels lead to depression and bad mood. As such, L-theanine maintains the balance of serotonin and dopamine levels in the body. Dopamine is also related to the happiness of an individual that means if you take L-Theanine on a regular basis, you could see a great drive in your sexual life and work life. Patients who often deal with depression are sometimes advised to take L-Theanine to increase their dopamine level.

11. Useful For Patients Suffering From High Blood Pressure

When L-theanine reduces the overall level of stress hormones, it could help in lowering blood pressure too. As such, low BP patients are often adviced not to consume this supplement because it could make the situation worse. As L-theanine improves one’s mood, when high BP patients consume it, chances of getting high BP decreases. The increase in serotonin and dopamine level drives the high blood pressure to a lower level.

12. Helpful For Autism

Autism, also called Autism Spectrum Disorder, is a developmental disorder in which the patient is unable to interact and communicate appropriately. Often people with autism tend to show aggressive behavior or feel anxious. L-theanine strikes a calming effect and regulates glutamates that help to control the behavior of neurotransmitters. Children with autism tend to feel annoyed just because they don’t feel happy. As L-theanine tends to increase the happiness neurotransmitter (dopamine), these kids would tend to feel better and less irritable.

13. Helpful For ADHD

L-theanine not only helps patients with schizophrenia, but it also deals with ADHD patients. ADHD may also hamper one’s sleep. In a study, it was discovered that boys who took two 200mg doses of L-theanine daily, for 6 weeks, had an improved quality of sleep.

14. It Is Neuroprotective

L-theanine provides neuroprotection for Parkinson’s disease-related neurotoxicants. Also, L-theanine relieves symptoms of Parkinson’s disease. PD is a neurodegenerative disorder and a common movement disorder that is characterized by tremors of the limbs, stiffness, and impaired balance.

15. Has Antiobesity And Antidiabetic Effects

The antioxidants present in L-theanine promotes better digestive health. The catechins, in the theanine, lower the activity of digestive enzymes and due to this intestines aren’t able to absorb all the calories consumed. Thus L-theanine provides an antiobesity effect, suppresses body weight increase and fat accumulation, as well as exerting antidiabetic effects.

16. Reduces The Likelihood And Severity Of Stroke

A stroke is a surprising blockage of blood in any part of the brain which further result in extreme chemical stress and death of brain cells. Studies have shown that theanine has the property of helping to reduce the likelihood of a stroke occurrence. It increases the nitric oxide in the artery lining cells which has the potential to lower the risk of a stroke.

17. Skin Benefits

Many skin care companies are beginning to include L-Theanine in their products. L-Theanine provides nourishment and moisturizes skin due to its potent antioxidant properties. Theanine is also effective for acute cutaneous inflammation.


Side Effects Of L-Theanine
Side effects of L-theanine could occur especially when too much of its supplement is consumed. These side-effects include; diarrhea, dizziness, headache, and pregnancy complications. Furthermore, due to theanine’s impact on hormone production, pregnant and nursing mothers should avoid consuming it.