L-Theanine Dosage, Benefits, & Concerns

Everyone knows that green tea boosts mental focus and supports brain function. The same goes for black tea. What you may know is that l-theanine, a non-essential amino acid, is largely responsible for these benefits. 

Also known as N-ethyl-l-glutamine, this compound is marketed as a natural nootropic and adaptogenic agent. 

Simply put, it keeps your brain sharp and may enhance your body’s ability to cope with stress. Clinical evidence shows that it may improve cognition, executive function, and verbal fluency in people with stress-related disorders. 

The right l-theanine dosage can take your workouts to a whole new level. You may find it easier to stay focused in the gym and create the mind-muscle connection needed for size gains. Plus, you’ll sleep better at night, which can lead to faster recovery from training. 

What we like most about l-theanine is that it calms the mind and body without drowsiness. Some studies suggest that it may also lower blood pressure, ward off anxiety, and boost immune function. That’s what we’ll discuss today. 

So, how does l-theanine work and what makes it so effective? Most importantly, is it safe? Let’s take a closer look at its health-promoting abilities! 

What Is L-Theanine?

L-theanine is a non-proteinogenic amino acid that occurs naturally in Camellia sinensis (the green tea plant) and other plant species. In addition to its neuroprotective action, this nutrient contributes to the umami taste of green tea.

The average cup of tea provides about 25 milligrams of this compound, reports a 2016 review published in Nutrients. After ingestion, it crosses the blood-brain barrier and reaches peak concentrations within 30 to 120 minutes. 

In clinical trials, l-theanine has been shown to improve diabetes symptoms, prevent obesity, and reduce fat storage in the body. Researchers believe that it may inhibit the expression of certain genes responsible for glucose uptake and fat accumulation. 

But what makes it stand out is its ability to ward off stress and promote relaxation. Here at Old School Labs, we’ve added l-theanine to Vintage Bright™, our brain health formula. 

Vintage Bright™ enhances cognitive performance, memory, and mental focus so that you can reach peak performance inside out outside the gym. 

It also contains ginseng, caffeine, bacopa herb extract, and other natural ingredients with nootropic properties. You can even use it as a light pre-workout to boost your energy before hitting the weights room!  

Camellia sinensis isn’t the only plant containing l-theanine. This amino acid can be also found in black and white teas, matcha tea, oolong tea, and some fungal species. It’s also available in supplement form. 

Your body cannot produce l-theanine on its own, so you have to obtain it from food. Although this compound isn’t essential for humans, it benefits your brain and overall health. 

Let’s see how it works!

How Does L-Theanine Work?

Unlike most amino acids, l-theanine has no role in protein synthesis. Instead, it interacts with GABA, dopamine, serotonin, and other neurotransmitters. As a result, it influences your mood, alertness, energy, appetite, sleep, and memory. 

Research published in the journal Beverages suggests that l-theanine modulates brain function through several mechanisms. 

First of all, it increases the production of alpha waves, leading to better sleep without drowsiness. At the same time, it decreases resting heart rate, which may help your body relax. 

Using as little as 250 to 400 milligrams per day can significantly improve sleep quality, according to the above review. 

Alpha brain waves are responsible for the state of mind you experience during meditation and daydreaming. 

L-theanine enhances alpha waves, helping you relax without worrying about feeling fatigued. On top of that, it reduces the levels of excitatory brain chemicals, which can further increase relaxation and protect your brain against stress. 

L-theanine may also enhance cognition and learning abilities. It becomes even more potent when combined with caffeine. Some studies indicate that it may slow down cognitive impairment in older adults and reduce mental stress. 

The same source notes that theanine helps the brain produce γ-aminobutyric acid, a neurotransmitter that regulates serotonin and dopamine levels. This may lead to better mental health and increased cognitive performance. 

According to the above source, this compound may also boost immunity and prevent upper respiratory tract infections by enhancing lymphocyte function. It appears to be even more effective when used along with cysteine, a non-essential amino acid. 

All in all, l-theanine can be considered a functional food additive. When administered in the right dose, it may reduce the symptoms of anxiety, stress, depression, and burnout. 

Fight Stress and Anxiety Naturally

As you already know, stress and anxiety can hamper your gains. When secreted in large amounts, cortisol — the stress hormone — affects your body’s ability to produce testosterone. As a result, you may have difficulty recovering from training and building muscle. 

L-theanine may help reduce stress and anxiety symptoms, according to a recent review published in Plant Foods for Human Nutrition. Researchers suggest taking 200 to 400 milligrams per day to reap the benefits. 

A 2019 study featured in Nutrients reports similar findings. Subjects took either 200 milligrams of l-theanine per day or placebo tablets.  

The treatment group experienced significant improvements in stress-related symptoms in just four weeks. Their verbal fluency, sleep quality, and execution function scores improved too. No side effects have been reported. 

Scientists attribute the anxiolytic, antidepressant, sedative, and cognitive-enhancing effects of l-theanine to its role as a partial agonist for the N-methyl-D-aspartate receptor. Therefore, this compound may boost mental health and mitigate the impact of stress. 

As discussed earlier, l-theanine may also lower blood pressure and heart rate. 

These beneficial effects can help foster a state of calm. A quality l-theanine supplement may come in handy for athletes, students, and individuals dealing with work-related stress. 

Get a Better Night’s Sleep 

Adequate sleep is just as important as clean eating and training when it comes to building mass. It’s actually one of the most effective recovery strategies for athletes, according to current research. 

Your body recovers from training and releases anabolic hormones while you sleep. 

Growth hormone, for example, is produced by the pituitary gland during non-rapid eye movement (NREM) sleep. It not only helps with muscle repair but also promotes hypertrophy and supports athletic performance. 

Sleep deprivation can affect your gains, recovery time, and cognitive function. This doesn’t mean you should start popping pills, though. Sometimes, a cup of tea is all you need to enjoy better sleep. 

As a naturally occurring compound in tea, l-theanine may improve sleep quality and duration, states the journal Beverages. 

In a clinical trial conducted on patients with generalized anxiety disorder, those who took 450 to 900 milligrams of l-theanine daily for 10 weeks reported better sleep than the placebo group. 

Another study investigated its effects on children with ADHD. 

Subjects who took 200 milligrams of l-theanine twice a day for six weeks experienced major improvements in sleep quality with no side effects. Therefore, this supplement is safe and effective even when administered in high doses. 

Decaf green tea contains a similar amount of l-theanine as caffeinated green tea. If you have trouble sleeping, you can either take l-theanine supplements or drink a cup of green or black tea with reduced caffeine content.

The Truth about L-Theanine and Fat Loss 

L-theanine may also aid in weight loss, reports a 2017 study published in BioMed Research International. This amino acid regulates nutrient absorption and may have beneficial effects on carbohydrate and lipid metabolism. 

Researchers say that it suppresses dietary fatty acids uptake and lowers blood sugar levels, which in turn may reduce fat storage. The study was conducted on rats, so further research is needed to determine how these findings translate to humans. 

Another study evaluated the anti-obesity effects of l-theanine, caffeine, and tea catechins on body weight. Mice fed with these compounds for 16 weeks experienced a reduction in body weight, triglyceride levels, and fat accumulation. 

At this point, it’s hard to tell whether or not l-theanine promotes fat loss. What we know for sure is that green tea can indeed prevent weight gain and speed up your metabolism. L-theanine may be partly responsible for these beneficial effects. 

Keep Your Immune System Strong 

A lesser-known benefit of l-theanine lies in its ability to improve immune function. In a small study, mice treated with l-theanine and l-cysteine for just two weeks experienced an increase in antigen-specific IgM and IgG levels, which protected them against the flu. 

Human studies report similar results. In a clinical trial, l-theanine and l-cysteine enhanced the immune response to the flu vaccine in older adults. 

Research also suggests that these amino acids may alleviate post-surgery inflammation and speed up recovery. In previous studies, l-cysteine and l-theanine restored natural killer cell activity in bodybuilders, reduced the incidence of common colds, and suppressed the release of inflammatory cytokines.

L-Theanine Dosage Recommendations 

Since l-theanine is not an essential nutrient, it’s unclear how much of it you need to reap the benefits. To date, there are no reported adverse effects associated with this compound. Some studies have used daily doses of up to 900 milligrams of l-theanine. 

Most supplements, including Vintage Bright™, contain around 200 milligrams per tablet. Take up to 400 milligrams per day and adjust the dosage if necessary. 

This amino acid often is administered along with caffeine and other nootropics or adaptogens. If you’re sensitive to stimulants, take l-theanine alone or in combination with ginseng, ashwagandha, Rhodiola rosea, and other herbal supplements that promote brain health. 

L-theanine and caffeine, for example, work synergistically to boost your energy and reduce fatigue. 

In a randomized clinical trial, subjects who took these compounds together completed cognitively demanding tasks faster and with greater accuracy than those taking caffeine alone. All in all, this combo may improve alertness and mental performance while increasing your energy levels. 

So, how do you get l-theanine into your diet? 

L-theanine is cheap and widely available. Add it to your pre-workout, mix it into protein shakes, or take it with your morning coffee. Better yet, try Vintage Bright™, our brain support formula. Like all of our products, it’s formulated with 100% natural ingredients in FDA-certified facilities. 

You can either swap your afternoon coffee for green tea or take l-theanine supplements. Another option is to drink a cup of decaf green tea before bedtime to help your body relax and catch more Zzz’s. 

Boost Your Brain Power Naturally 

This amino acid is clinically proven to reduce mental and physical stress. It also has beneficial effects on cognition, mood, sleep, and other aspects of mental well-being. Plus, it’s safe and has no side effects. 

As far as l-theanine dosage goes, there are no set recommendations. Our advice is to stick to 400 milligrams per day and see how your body reacts. For increased energy, choose a formula that contains both l-theanine and caffeine. 

What’s your take on l-theanine and nootropics, in general? Would you recommend any ingredient in particular? Let us know your thoughts below!