How Supplementing With L-Theanine Can Improve Your Sleep And Calm Your Mind

August 15, 2017 |


L-theanine is an amino acid found in green tea with amazing health benefits. Research shows that supplementing with l-theanine may be able to help balance your sleep-wake cycle, reduce depression and anxiety, boost your mood, and leave you feeling pleasantly calm.

As one of the few supplements that cross the blood-brain barrier, there are no limits to what l-theanine can do! In addition to improving your brain chemistry, l-theanine can also burn fat, balance alcohol levels in the bloodstream, support liver health, and counteract the jittery effects of caffeine. Here is everything you need to know about l-theanine and how to use it in supplement form.

Quick Facts About L-Theanine

  • L-theanine is an amino acid found in green tea that has been shown to make you feel calm and alert at the same time.
  • L-theanine burns fat, reduces anxiety and depression, decreases the impact of strokes, supports brain and liver health, balances alcohol in the bloodstream, and counteracts the effects of caffeine.
  • L-theanine is one of the few dietary supplements that crosses the blood-brain barrier.
  • L-theanine reduces anxiety without impairing motor skills or causing sleepiness.
  • L-theanine is one of two compounds responsible for giving green tea its rich and savory flavor.

How Does L-Theanine Work?

L-theanine is a a neurotransmitter that produces a calming effect on the brain. It works by counteracting another neurotransmitter in the brain called glutamate that causes excitement. L- theanine blocks glutamate by binding to the same receptors in the brain, which produces an inhibitory effect that makes you feel calm instead of excited (1).

Along with blocking the excitatory neurotransmitter glutamate, l-theanine stimulates the production of another calming neurotransmitter called GABA. Many prescription drugs work by boosting the production of GABA in the brain. But studies show that l-theanine creates a calming and anti-anxiety effect on the brain without making you sleepy or impairing your motor skills (1). On the other hand, prescription drugs may leave you feeling groggy and even more tired the next morning.

Further research shows that supplementing with l-theanine improves alertness while producing a calming effect on the brain at the same time. Supplementing with l-theanine also prevents blood pressure spikes that many people feel when they are stressed (1).

Newer research shows that l-theanine has beneficial effects beyond its anti-anxiety properties. Excessive amounts of glutamate in the brain are associated with the development of neurodegenerative disorders, schizophrenia, and stroke. L-theanine’s ability to inhibit glutamate makes it a promising supplement for the prevention of these conditions.

There is also evidence to show that l-theanine has influence over genes in the brain that are responsible for aggression, fear, and memory. This means that l-theanine could possibly be used to improve mood disorders, substance abuse, and post-traumatic stress disorder (1).

Health Benefits of L-Theanine

L-theanine has a wide range of health benefits on the body. It has been shown to improve sleep, prevent neurodegenerative diseases and stroke, burn fat, and more.

1. L-theanine improves sleep. 

A 2011 study from Japan stated that l-theanine can be used to improve sleep quality due to its ability to counteract glutamate (3). The study also found that l-theanine counteracts the stimulatory effects of caffeine and lowers blood pressure. It has anti-anxiety properties that increase the “happiness” neurotransmitters serotonin and dopamine while decreasing norepinephrine, which is a neurotransmitter that acts similar to the hormone adrenaline by causing you to feel anxious (3).

Lastly, the study stated that l-theanine increases alpha brain wave activity, which are the brainwaves that are present when you are meditating or when your mind is peaceful (3). L-theanine decreases the stress hormone cortisol and provides neuroprotection from glutamate toxicity (3). In other words, taking l-theanine induces a feeling of relaxation that your body would normally feel while recovering from a stressful task.

2. L-theanine protects against neurodegenerative diseases.

Other research shows that l-theanine reduces the harmful effect of stress on the brain’s cells to help protect them from neurodegenerative diseases. One study, in particular, investigated how stress makes it harder for you to think clearly and make the right decisions. The study found that animals who were put in stressful situations did worse on learning and memory tests. They also had elevated levels of oxidative stress in the brain and increased amounts of the excitatory hormone adrenaline.

But treating the animals with l-theanine before the stress was applied reversed their cognitive impairment as well as the oxidative damage done to the brain. It also reduced their stress hormones (1). This study shows that l-theanine contains properties that may be able to reverse and protect against Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis (ALS).

3. L-theanine prevents strokes.

L-theanine can be used to repair the brain after a stroke. It can also help prevent a stroke from occurring in the first place. Studies show that l-theanine increases the amount of nitric oxide inside cells. Nitric oxide is needed to communicate signals regarding blood flow and pressure to the artery walls. Nitric oxide tells the artery walls when they should relax or constrict to properly distribute blood flow. Because l-theanine increases nitric oxide, it has the potential to lower the risk of stroke (1).

Another way that l-theanine prevents a stroke is by blocking an inflammatory protein known as tumor necrosis factor alpha (TNF-a) from binding to blood vessels and causing a blockage or obstruction that would limit blood flow to the brain (1). After a stroke occurs, l-theanine protects the rest of the body from damage by refilling the rest of the body with blood after it has been cut off during the stroke (1).

Research shows that taking l-theanine 12 hours after a stroke may help reduce the amount of damage done to the brain. Even taking l-theanine 24 hours after a stroke helped improve recovery (1).

4. L-theanine supports liver health and fights the effects of alcohol.

Research shows that l-theanine works to protect the body against the effects of alcohol. One study found that mice who were given l-theanine either before or after they were given alcohol had lower levels of blood alcohol. The study found that l-theanine reduces blood alcohol levels by modulating the chemistry of the alcohol (4).

Once inside the body, alcohol converts into a chemical known as acetaldehyde, which is more toxic than alcohol itself. L-theanine breaks down acetaldehyde and blocks its toxic free radicals from harming healthy cells. Research shows that l-theanine not only blocks the toxic free radicals caused by alcohol, but it also lowers the levels of blood alcohol to below normal for five hours (4).

L-theanine is able to reduce the effects of alcohol because of its ability to restore a powerful antioxidant found in the liver called glutathione. Alcohol reduces the amount of glutathione in the body. If you only drink occasionally, the liver is able to restore your levels of glutathione. But when you drink a lot, glutathione becomes chronically suppressed and your liver can’t keep up. L-theanine can be used to counteract alcohol’s suppression of glutathione. Some researchers are even considering adding l-theanine to cancer treatment to boost levels of glutathione that are killed off by chemotherapy (4).

5. L-theanine burns fat and prevents weight gain.

Two studies showed that taking l-theanine can reduce depression and increase your motivation to work out, which can help burn fat. According to researchers in the United Kingdom, mountain climbers who drank hot tea containing l-theanine improved their fatigue levels (4). A Finnish study supported the claim that l-theanine reduces depression by concluding that depressed people who drank five cups of tea a day or more reduced their symptoms (4).

Unlike caffeine, which can leave you feeling tired and shaky when you drink too much, l-theanine burns calories while calming you down. It also helps you feel motivated. Japanese researchers conducted a study in 2004 to measure the weight loss effects of l-theanine against several other compounds in tea, such as caffeine, catechins, and green tea powder itself. Results showed that l-theanine can prevent fat accumulation and weight gain similar to caffeine, but without the jittery effects. It was also shown to reduce triglyceride levels in female mice (4).

L-Theanine Supplements

How To Take L-Theanine

L-theanine supplements should be taken as directed by the label on your supplement bottle. If you are using l-theanine as a natural sleep aid, take it approximately one hour before sleep to help you relax. L-theanine is non-drowsy and can be used any time of the day to promote calmness without making you feel sleepy or impairing your motor skills.

How Much L-Theanine Should You Take?

There is no daily recommended dosage of l-theanine. One study involving 40 patients with schizophrenia showed that the subjects saw improvements in their symptoms when they took 400 mg of l-theanine along with their normal medications for eight weeks. Subjects reported feeling less anxious and had general improvements in their mental health (1).

Another study found that taking 250 mg of l-theanine each day improved sleep quality and a number of other symptoms. Taking a combination of 400 mg per day of l-theanine with 50 mg of the hormone pregnenolone reversed anxiety and other negative symptoms associated with the condition (1).

To find the right dose for you, pay attention to how you feel. L-theanine will not make you drowsy, so you can experiment with different amounts safely. As with any supplement, try not to take more than you need. If you have been taking l-theanine for a long time, it might be a good idea to cycle your dosage to give yourself a break and keep the supplement working well for you. For example, take it for three days on and one day off.

Can I Take L-Theanine With Melatonin?

There is no evidence to show that l-theanine cannot be taken with melatonin. In fact, taking the two together may help you sleep! L-theanine provides a calming effect while melatonin makes you sleepy.

Does L-Theanine React With Any Prescription Drugs? stated that there are no interactions between l-theanine and other drugs (6). But according to WebMD, l-theanine may interact with the following medications (5):

High blood pressure medications: L-theanine appears to decrease blood pressure. Taking it with high blood pressure medications may cause your blood pressure levels to drop too low. Examples of blood pressure medications include losartan, captopril, hydrochlorothiazide, enalapril, valsartan, amlodipine, diltiazem, furosemide, and more.

Stimulant drugs: L-theanine may interact with stimulant medications and cause them not to work. Examples of stimulant drugs include pseudoephedrine, epinephrine, diethylpropion, phentermine, and more.

Possible Side Effects of L-Theanine

Studies show that l-theanine doesn’t typically produce drowsiness or impaired concentration like a prescription sleep aid might (3). However, everyone reacts differently to nutritional supplements. According to, l-theanine may produce gastrointestinal distress, headaches or dizziness (6). The Food and Drug Administration labeled l-theanine has been labeled as generally recognized as safe or GRAS (6).

Who Shouldn’t Take L-Theanine?

Unlike drinking large amounts of tea, l-theanine supplements should not cause an upset stomach or make you feel jittery from too much caffeine. It is always best to consult a doctor before supplementing with l-theanine if you have concerns. L-theanine is considered safe for people of all ages as it is caffeine-free and derived naturally from tea.

It is unsure if l-theanine is safe for women who are pregnant or breastfeeding. L-theanine may interact with blood pressure medication; therefore, people on high blood pressure medicines should speak with their doctor before taking it. People who use stimulants may also want to avoid taking l-theanine.

Is L-Theanine Safe for Children?

Studies show that l-theanine is safe enough for children. According to a 2011 study, boys aged 8 through 12 years old with attention deficit hyperactivity disorder (ADHD) saw improvements in their sleep when they took 400 mg of l-theanine. The study concluded that l-theanine is a safe and effective way to improve sleep in children with ADHD even at relatively high doses of 400 mg (2). Consult with your child’s pediatrician before giving your child more than 400 mg of theanine.