L-Theanine: Benefits, Side Effects & More (Ultimate Guide)
What is L-Theanine?
L-theanine is something that you’ve most likely had before, whether it was in black tea, green tea, matcha, or mushrooms!
This amino acid, also known as γ-glutamylethylamide, was first discovered in tea leaves by Japanese scientists back in 1949.
L-theanine is non-essential to the human body. Still, it has gained momentum in the supplement industry for its beneficial effects on our brain, emotions, and stress levels.
When we consume these teas or take L-theanine as a supplement, it can influence the balance of chemicals in our brain, improving our mood, sleep patterns, and emotions.
Keep reading to learn all there is to know about L-theanine. You’ll probably find that it could be worth adding this nootropic to your morning supplement regime or choosing green or black tea for your next hot beverage!
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L-Theanine Benefits
1. Mental Focus & Memory
Taking L-theanine has shown to have many benefits when it comes to our attention and memory.
In one study, they found that a single dose of 100.6mg of L-theanine “increased correct answers and decreased the number of omission errors in the working memory task.” The heightened attention from taking L-theanine resulted in improved memory and mental skills.
In another study, L-theanine showed promising influence on speaking and writing skills. Administration of 200mg of L-theanine a day for four weeks improved verbal fluency (especially letter fluency) and executive function, showcasing a drastic change from their pre-assessment performance levels.5
If you’re consuming green tea or black tea, you are ingesting other compounds besides L-theanine, such as caffeine! We will highlight more of these benefits later. Still, we will note that one of the beneficial synergistic effects of having L-theanine and caffeine together increases cognitive function and focus.
Lastly, it has also been shown that once in the body, L-theanine increases
a-wave activity. This essentially means that it helps us in task performance and mood!
2. Stress Reduction
L-theanine has been popular in the health and wellness world for its anti-stress properties. It can block L-glutamic acid from binding to glutamate receptors, which basically inhibits neuron excitation in our brain.
This can help us respond better to stressful situations. One study measured stress responses and anxiety levels in which L-theanine was orally taken by participants. The results of this study suggest that supplementing around 200-400mg/day may reduce anxiety and stress in those who are exposed to intense/stressful situations.
Participants who underwent mental tasks in a different study showed a dramatic reduction in their tension and anxiety scores with L-theanine compared with the placebo group. The placebo group did not take any L-theanine.
The study mentioned above found that administering 200mg of L-theanine per day for four weeks decreased stress-related symptoms safely and effectively.5 L-theanine could be your best friend in times of heavy workloads, tricky tasks, and upcoming deadlines!
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3. Better Immunity
Including L-theanine in your diet can also enhance immunity!
It has been shown to aid lung health by preventing upper respiratory infections since L-theanine enhances lymphocyte function.
In conjunction with cysteine, L-theanine also decreases unwanted inflammatory responses in the intestinal tract. The synergistic effect between 280mg of L-theanine and 700mg of cysteine even helped those in post-surgery recovery, supporting their immune system and reducing infection risk.
Although more studies are required for this particular benefit of L-theanine in humans, many animal studies support L-theanine’s immune-enhancing properties!
4. Reduced Blood Pressure
One study that looked into blood pressure in stressful situations produced promising results! L-theanine significantly decreased the blood pressure in participants who were more susceptible to stress-induced high blood pressure, even during strenuous mental tasks.
L-theanine’s natural relaxing and anti-stress properties contribute to helping anyone with stress-induced high blood pressure. According to studies, we see the same impact on heart rate: just 200mg of L-theanine showed to reduce resting heart rate, according to studies.
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5. Anticancer
L-theanine supplementation has been linked to anti-tumor effects on humans and animals, especially with other medicinal therapies.
This amino acid can even go as far as helping to alleviate some of the toxic burdens of those during cancer treatment. L-theanine reduces oxidative stress catalyzed by anticancer drugs.
Does L-Theanine Help Depression?
L-theanine does, in fact, help with depression! This has to do with L-theanine’s effect on heart rate; Because it reduces heart rate and stress levels, it can have an anti-depressive effect on those who use it!
In addition, the uplifting and calming feelings that L-theanine can have contributed to helping those who may struggle with depression. Increasing GABA levels (low GABA levels in the body are linked to anxiety, mood disorders, depression, and more), can help alleviate depression.
Does L-Theanine Make You Happy?
Since L-theanine can boost GABA levels and influence other chemicals/hormones in the brain it is safe to say that, yes! L-theanine can make us happy!
According to animal models, L-theanine increases brain serotonin, dopamine, and GABA levels, which is all about reinforcing feelings of happiness, motivation, and excitement.
In elevating these positive hormones, L-theanine can also promote
quality sleep by helping us have an extended non-REM rest. In promoting a healthy sleep cycle, L-theanine increases the chances of waking up feeling happier and more refreshed.
L-Theanine & Caffeine
We have already learned all the impressive nootropic ways of L-theanine. But what happens when we have it in combination with other things, like caffeine?!
I’ll tell you… magic! Consuming these two compounds together, whether by adding L-theanine to your coffee, drinking tea, or through supplements, produces a pronounced synergistic effect.
Here are some examples.
· When taken together, L-theanine and caffeine have been shown to improve performance (speed and accuracy) in mentally demanding tasks, as opposed to taking them separately12
· Heightened energy and awareness
· L-theanine reduces the adverse effects from caffeine: fewer energy crashes, headaches, and tendencies toward high blood pressure
· Enhanced creativity
To feel these benefits, how much are we talkin’?
Most sources say the ideal ratio of caffeine to L-theanine is generally 1:2, or 100mg of caffeine to 200mg of L-theanine.
Hint: We get roughly 100mg of caffeine in a cup of coffee!
L-Theanine Side Effects
You can enjoy your next cup of tea knowing L-theanine has no confirmed side effects!
L-theanine is considered generally safe, both through food and drink and by supplementation.
When drinking tea to reap the benefits of L-theanine, just consider the caffeine content, since black and green tea have around 38-47mg of caffeine per cup! Some individuals who are sensitive to caffeine may opt to take L-theanine in capsule form.
Additionally, it is not recommended to use L-theanine for long periods. It has been used safely for up to 8 weeks (900mg/day, in this case), but it is not recommended to take longer than this (the only reason being that mild symptoms such as headache, drowsiness, and sleepiness have been reported).
Other Precautions to Consider
There are not enough studies for pregnant or breastfeeding women to determine whether or not L-theanine is safe.
For children, L-theanine has been considered to help alleviate symptoms for those with ADHD, specifically for children from 8-12 years of age.
The results showed that L-theanine, when taken in two separate doses per day (400mg/day altogether) for 6 weeks, safely helped the sleep quality in those children.
However, more studies need to be done to ensure the safety of this age group.
Contraindications
Being mindful of the contraindications between medications you are currently taking with supplements you are thinking of taking is very important!
For instance, those who are on medications for high blood pressure, in addition to taking L-theanine, could be at risk for their blood pressure dropping too low.
Always talk to your healthcare provider first!
L-Theanine Dosage
Since more research needs to be done, the recommended allowance for L-theanine is not yet determined.
However, we see little to no adverse effects of L-theanine in even high doses (up to 900mg).
To be safe and achieve optimal benefits, supplemental L-theanine is typically available at around 200mg3. This would be a sufficient dosage for most healthy individuals.
Don’t forget about tea!
L-theanine might come in smaller packages here, but we know we are getting around:
· Black Tea: 25mg/cup
· Green Tea: 8mg/cup
· Matcha: 46/cup
Ways to Try L-Theanine
Just to recap, we can try incorporating L-theanine via:
Our Diet
· Black tea, green tea, and matcha
· Adding supplemental L-theanine (in powder form) to coffee, smoothies, etc.
Supplements
· Taking capsules (can be beneficial any time of day, depending on your
needs!)
Through Supplement Mixers
Since L-theanine has been growing in popularity, you may start noticing it in different supplement mixes and drinks.
One drink mix that contains 75mg of L-theanine is EarlyBird Morning Cocktail! This drink mix is definitely worth a try if you’re thinking about seeing how L-theanine can work for you.
This particular drink mix has a variety of other feel-happy and brain-boosting ingredients. It also contains natural sources of caffeine that, as we now know, works wonders with L-theanine!
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