The nonprotein water-soluble amino acid (AA), L-theanine (γ-Glutamylethylamide), is found in Camellia sinensis (green tea) leaves. It’s actually the main component of green tea. In fact, it’s considered green tea’s most ample form of total AAs (around 50%).
It was identified in 1948 in Japan as a green tea constituent, and while it’s found mostly in the tea plant, it’s present in a few other plants, such as mushrooms like Boletus badius.
Although L-theanine is synthesized in plants’ roots, it concentrates in the leaves. It can impact important brain chemical messengers (neurotransmitters) positively that are involved with sleep, mood, and stress. It seems to play a role in GABA formation. This is a neurotransmitter that works similar to a “brake” during stressful times.
L-theanine helps initiate balance in your neurotransmitter system, leading to improvements in the physical and emotional/mental disturbances that result from being overly stressed.
What Does L-theanine Do in Your Body?
Some ways L-theanine works in your body include:
1. Promotes a Calmness Feeling
Although L-theanine helps to increase chemicals that calm you down, it can also decrease your brain’s levels of chemicals linked with stress and anxiousness.
Your brain begins producing hormones like corticosterone and cortisol when you’re stressed.
2. Neurotransmitter Boost
An adequate dose of L-theanine helps boost your levels of brain chemicals that produce a “calm” feeling, such as serotonin, GABA, and dopamine.
These neurotransmitters assist your brain in regulating:
- Ability to sleep
Therefore, if you increase your levels of calming brain chemicals, it could help you relax and sleep more easily.
3. Nootropic Effects
Taking an L-theanine supplement offers a cognitive enhancing (nootropic) effect. Research shows, taking this amino acid before you take a test helps improve focus and reduce errors.
This calming brain effect might also help keep your mind from wandering when you’re trying to stay on task and recall information.
4. Enhance Alpha Brain Waves
L-theanine is an anxiolytic, and therefore, helps amplify/enhance alpha brain waves. These are also present when you let your mind wander or when you meditate. Alpha waves also occur during REM sleep as your sleeping brain is still in “wakeful relaxation” mode.
L-theanine may help you replicate some of the creativity-oriented effects and focus on your experience during meditation.
Taking a Closer Look at How L-theanine Helps with Sleep, Stress, and Anxiousness
L-theanine is most recognized for helping people relax. However, it’s also been shown to help with sleep, stress, and anxiousness.
L-theanine for Sleep
Obtaining proper sleep is more than just falling asleep and waking up eight hours later. During sleep, your body is washing your brain with cerebral spinal fluid. This allows your neurons to communicate with one another and eliminates toxins your brain builds up when you’re awake.
In your brain’s pineal gland, serotonin converts to melatonin. Therefore, when you improve your levels of serotonin, it ultimately leads to improved melatonin levels, supporting restful sleep.
There are several studies that suggest L-theanine might potentially help individuals relax before bedtime, obtain sleep more easily and even experience deeper sleep.
These benefits might come from the certain effects l-theanine has on your brain chemicals that have a role in sleep.
One study in 2018 found that individuals who took 450 mg to 900 mg of L-theanine each day for eight weeks reported experiencing greater sleep satisfaction. The participants in the study were taking antidepressants for generalized anxiety disorder.
In another study, 30 healthy individuals were given either a placebo or 200 mg of L-theanine for four weeks. When compared to those taking the placebo, those taking the L-theanine:
- Took less time to fall asleep
- Took less sleep medicines
- Experienced fewer sleep disturbances
They also experienced enhanced mental clarity, which isn’t a surprise after getting a good night’s sleep.
L-theanine’s alpha brain-boosting abilities could help your body and brain enter the NREM sleep stage (first stage) where your alpha brain waves are at their highest level. L-theanine supplementation could help you fall asleep easier and quicker at bedtime because of its relaxation-boosting abilities. This amino acid doesn’t work as a sedative, but rather promotes relaxation and lowers anxiousness levels.
L-theanine for Stress
Often, people forget that chronic stress isn’t just annoying, but could also lead to ill health because it alters the responses of the adrenal axis and the sympathetic nervous system. This upregulates free radical damage and inflammation and increases your flow of stress hormones.
If you understand the biology of stress and the way it works on your body, then you’d likely make choices that would help you restore yourself and relax. This might include taking natural aids that support, replenish and soothe your tissues, cells, and organs.
Your hypothalamic-pituitary-adrenal (HPA) axis is the main axis of your body’s endocrine organs that adjusts in response to stress. It affects the function of a lot of your other biological processes and systems through the cortisol hormone. Chronic stress is associated with chronically increased salivary cortisol levels in both adults and children. These high levels are linked to decreased immune response, impacting healing and prolonging recovery time.
Research shows L-theanine reduces stress and promotes relaxation, potentially through increased alpha wave activity. It also blocks L-glutamic acid-binding to excitatory glutamate receptors in your central nervous system.
L-theanine for Anxiousness
L-theanine’s anti-anxiousness effect comes from increased GABA synthesis and enhanced alpha brain wave activity. In turn, increased GABA increases your brain’s levels of serotonin and dopamine, which results in general feelings of well-being and calm.
Typically, most people note a calming effect within 30 to 40 minutes of taking a 50 mg to 200 mg dose of L-theanine. This usually lasts around eight to 10 hours. A regimen of 200 mg once or a couple of times a day helps improve moderate anxiousness symptoms. However, if you’re experiencing more severe anxiousness symptoms, you’ll want to try higher doses (600 mg to 800 mg), but space them out throughout the day in 100 mg to 200 mg increments.
Unlike conventional anti-anxiousness therapies like benzodiazepines, L-theanine doesn’t cause things like:
- Slowed reflexes
- Increased drowsiness
- Impaired concentration
There’s no risk of developing a dependence or tolerance and there haven’t been any reports of severe negative interactions or side effects with other synthetic drugs or natural products.
The Journal of Clinical Psychiatry published a study that focused on individuals living with a schizoaffective disorder or schizophrenia in general. Researchers of the study found that L-theanine improved their symptoms and reduced their anxiousness.
Is L-theanine Safe to Take?
The FDA has put the “generally recognized as safe” classification on L-theanine after taking advice from experts. This classification means the FDA believes it’s safe when you use it as the packaging directs. But, pregnant women or those who are breastfeeding shouldn’t use L-theanine.
How Much of L-theanine Should you Take?
The dosages of L-theanine will vary. Since it’s a relatively safe supplement, you can take it in a dosage that ranges from 25 mg (one cup of green tea) to 500 mg (high dosage pills). You’ll want to begin slowly and work your dosage up until you find a dosage that’s right for you. If this is your first time taking L-theanine, begin with one cup of tea, which will help to relax you and provide you with a better headspace to sleep.
Most individuals become exposed to stress every day, whether it’s due to family, bills, work, taxes, or just the state of the world around them. Making the commitment to relaxation is an important part of overcoming the array of mental pressures you’re exposed to. If you’re looking for an easy and effective way to experience a relaxing boost to unwind after a long day, L-theanine might be just what you’re looking for.