- L-theanine, naturally found in tea and mushrooms and also available as a supplement, has exhibited positive effects in people with anxiety
- L-theanine has been shown to have a beneficial effect on symptoms of anxiety in doses of 200-400 mg daily for up to 8 weeks
- Side effects of L-theanine are rare and it is generally considered a safe supplement with low toxicity, but it may interact with some medications and other supplements
With over 40 million adults in the U.S. having an anxiety disorder, anxiety is the most common mental health concern in the United States. (Source)
There are many tactics commonly recommended to manage anxiety such as maintaining a healthy diet, getting regular exercise, practicing breathing techniques, and limiting time on your phone.
There is also research to show that some supplements might be beneficial in alleviating anxiety. One of these is L-theanine.
Learn about the recommended L-Theanine dose for anxiety and how it works in your body.
What Is L-Theanine?
L-theanine is an amino acid. The human body does not produce it, and we do not need it to survive.
L-theanine is naturally found in green tea and black tea and some mushrooms contain small amounts of it too, but it is otherwise scarce in nature.
When ingested, L-theanine is thought to exhibit effects on the brain within 30 minutes. (Source)
It may affect brain activity by promoting calm brain waves, regulating certain neurotransmitters including GABA, which works to calm the brain, serotonin (“the happy hormone”), and dopamine (“the feel-good hormone”), while also lowering blood pressure.
How Does L-Theanine For Anxiety Work?
Research does suggest that L-theanine has the potential to promote mental health in those with stress-related ailments.
A recent study investigating the effects of four weeks of L-theanine supplementation (200 mg/day) on healthy adults without any major psychiatric disorders found a significant improvement in measures of anxiety and stress. (Source)
It is thought that L-theanine imparts these benefits by promoting calm brain waves, regulating neurotransmitters, and lowering blood pressure.
Promoting Alpha Brain Waves
It has been reported that L-theanine can increase alpha brainwave activity.
Alpha brain waves are produced by your brain when you’re not focusing too hard on anything in particular. You might be meditating or daydreaming. Whatever you’re doing, you’re probably feeling relatively calm and relaxed.
Anxiousness is associated with a decrease in these alpha waves in the brain, whereas when we experience an increase in alpha brain waves, we’re likely to feel fewer symptoms of depression and anxiety. (Source)
Another way L-theanine reduces anxiety is by reducing the effect of glutamate on the brain. (Source)
Glutamate is the major excitatory neurotransmitter that is crucial for learning and memory.
Low levels of glutamate can lead to fatigue, brain fog, and poor memory while high levels can cause restlessness, inability to concentrate, insomnia, and anxiety.
Our bodies naturally balance excess glutamate with a compound called gamma-aminobutyric acid (GABA).
L-theanine can increase levels of GABA, which in turn decreases glutamate levels.
At the same time, L-theanine can also block glutamate receptors in the brain. In doing this, it prevents glutamate from binding to the receptors, reducing overall glutamate levels and allowing more GABA to circulate, inducing calm in the brain.
In animal models, L-theanine has also been seen to increase levels of the neurotransmitters serotonin and dopamine. (Source)
Lowering Blood Pressure
L-theanine may also play a role in reducing anxiety by lowering blood pressure.
Stress and anxiety are known to increase blood pressure by constricting blood vessels.
One study found that L-theanine acts as a hypotensive agent with anti-stress activity, controlling rising blood pressure in times of high stress. It does this by stimulating the production of nitric oxide, a compound that dilates blood vessels and lowers blood pressure. (Source)
By inhibiting blood pressure increases during times of stress, L-theanine can help to ease anxiety.
Does L-Theanine Help With Panic Attacks?
There is very little evidence that L-theanine is an effective treatment for panic attacks.
However, because it can be helpful in calming feelings of anxiety, it may be beneficial to take preventatively if you are prone to panic attacks, or when feelings of anxiety and panic are rising.
Any Possible Side Effects?
Most people are unlikely to experience side effects when they take L-theanine and it is generally considered a safe supplement. (Source)
An animal study investigating the toxicity of L-theanine found that it has extremely low toxicity. No toxic effects were seen even at doses as high as 4,000mg per kg of body weight for 13 weeks. (Source)
However, women who are pregnant or breastfeeding should not use L-theanine.
There have been some reports of L-theanine worsening anxiety, but this was only seen with very high doses or due to interactions with other medications.
It is essential to consult a doctor before taking L-theanine supplements if you are on medication as it can interact with the following drugs and supplements:
- drugs for the treatment of high blood pressure
- other supplements that lower blood pressure
- stimulants, such as those that doctors use to treat attention deficit hyperactivity disorder (ADHD)
- supplements that contain caffeine
What Dosage Of L-Theanine Helps With Anxiety?
As L-theanine is not a medication, there are no official guidelines stating how much a person should take. However, due to its low toxicity, it is unlikely to cause an overdose.
L-theanine is usually available in the form of 200mg tablets and has most often been used by adults in doses of 200-400 mg daily for approximately 4-8 weeks.
In one study, supplementation with 200mg of L-theanine in a group of healthy adults with no major psychiatric illness for four weeks resulted in a decrease in stress-related symptoms (i.e., depression, anxiety), an improvement in cognitive function, and a reduction in sleep quality problems. (Source)
Data from another study suggests that L-theanine administered at daily doses ranging from 200 to 400 mg for up to 8 weeks are safe and induce anxiolytic (anxiety-reducing) and anti-stress effects in both acute and chronic conditions. (Source)
Research examining whether L-theanine is effective for patients with major depressive disorder (MDD) suggests that administration of 250 mg of L-theanine daily for 8 weeks, alongside the participants’ current medication, is safe and has multiple beneficial effects on depressive symptoms, anxiety, sleep disturbance, and cognitive impairments.
However, since this is an open-label study, placebo-controlled studies are required to consolidate the effects. (Source)
If you are interested in supplementing with L-theanine, it is often recommended to start off with a low dosage for a couple of weeks. Observe how your body responds and then decide whether to increase your dose based on your body’s reaction.
You can also consult a doctor before taking supplements to get their advice on dosage if you are unsure.
How To Take L-Theanine
L-theanine is naturally found in tea.
L-theanine content of various teas: (Source)
- Black tea: 5.13 mg/g
- Green tea: 6.56 mg/g
- White tea: 6.26 mg/g
- Oolong tea: 6.09 mg/g
With approximately 3g of tea per cup, levels of L-theanine can range from 14.4g in a cup of black tea to 19.68g in a cup of green tea.
To reach 200mg of L-theanine per day, you would have to drink over 10 cups of green tea – which also means a lot of caffeine. Consuming large amounts of caffeine can lead to nausea, upset stomach, and irritability.
Women who are pregnant or breastfeeding should also limit how much tea they drink to avoid over-caffeinating.
And those taking chemotherapy drugs should talk with their healthcare provider before drinking large amounts of green tea because the polyphenol EGCG found in green tea has been seen to reduce some chemotherapy drugs’ efficacy, such as bortezomib. (Source)
There are various L-theanine supplements on the market.
These can come in tablet or powder form and usually contain 200mg per tablet or serving. Some good quality green powders include L-theanine too.
Human Tonik powders are fully transparent with their ingredients and dosages, never relying on proprietary blends, and are third-party tested, making them a good choice if you’re looking to try out a greens powder supplement with L-theanine.
L-theanine, an amino acid naturally found in tea and mushrooms but also available as a supplement, has been shown to have positive effects on people with anxiety.
It is thought that L-theanine does this by promoting calm brain waves, regulating certain neurotransmitters, and lowering blood pressure.
Side effects are rarely experienced with L-theanine and it is generally considered a safe supplement with low toxicity.
However, it may interact with some medications and other supplements and so it is important to consult a doctor before taking L-theanine if you are on medication or a supplement program.
As L-theanine is not a medication, there are no official guidelines stating how much a person should take. But it has been shown to have a beneficial effect on symptoms of anxiety in doses of 200-400mg daily for up to 8 weeks.
Lucy Brennan is a registered associate nutritionist (ANutr) and freelance writer specializing in health, nutrition and wellness content. She holds a BSc. (First Class Hons) in Public Health Nutrition and has over 4 years’ experience working in health communication, which is where her passion lies.
She has worked in roles with The Irish Food Board and FleishmanHillard PR, on their healthcare team, working with national and international health companies. Using this experience, Lucy now writes content in a freelance capacity. Lucy is dedicated to providing evidence-based content that is both engaging and accessible and inspires readers to make informed choices regarding their health.