caffeine l-theanine main

Millions of people rely on their morning cup (or two) of coffee to wake up and get a boost of energy. As everyone knows, it’s the caffeine in coffee that’s responsible for the spike in energy. Everyone probably doesn’t know, however, that in addition to being a stimulant, caffeine is also considered a nootropic — a substance that has a positive effect on cognition.

Caffeine is a great nootropic, but it has one problem associated with it — caffeine comes with a side effect of nervousness and jitters for many people. Here, L-theanine comes to the rescue. L-theanine is an amino acid that counteracts the jitters without ruining the alertness buzz people expect and enjoy from caffeine. Additionally, L-theanine is a nootropic in its own right, so the combination of caffeine and L-theanine makes for one of the best and most popular nootropic combinations you can take.

Caffeine Has Cognitive-Enhancing Effects

You won’t be surprised to read that the most common source of caffeine is the coffee bean, but the bitter substance does occur naturally in many other plants including leaves from holly, guayusa, and tea plant leaves. There is also man-made (synthetic) caffeine which is added to some drinks, foods, and medicines.

Coffee drinkers are well-aware of caffeine’s stimulant effects, but probably very few realize that caffeine (chemical name 1,3,7-trimethylxanthine) is the world’s most commonly used psychoactive drug and a nootropic that improves thinking skills.

Caffeine is a nootropic because it provides improvement in a number of areas of cognition:

  • concentration
  • memory
  • alertness
  • mood
  • reaction time
  • attention
  • decision making

There are several factors that give caffeine its nootropic powers, the three main ones are listed here.

Caffeine Is An Adenosine Antagonist

In biochemistry, an antagonist is a substance that inhibits, or interferes with, the physiological action of another substance. Caffeine is an adenosine antagonist — it reduces the build-up of a neurochemical called adenosine. Here’s the significance of that.

Throughout the day countless neurons (brain cells) fire as they do their neurological work. A natural result of this action is a build-up of adenosine, which reduces neuronal activity and causes a person to feel less alert. The increase in adenosine brings about calmness and relaxation, and ensures that your brain doesn’t become over-excited. It turns out that caffeine is the same shape and size as adenosine. Because of this, it’s often caffeine that interacts with neurons in place of adenosine.

Caffeine in effect mimics adenosine and takes its place. But where adenosine slows down neuronal activity, caffeine speeds up activity. This adenosine antagonist property is the main reason caffeine brings about wakefulness and mental and physical alertness.

Caffeine taking the place of adenosine influences the release of several chemicals, including the neurotransmitters serotonin, adrenaline, glutamate, and dopamine. That’s a whole lot of feel-good chemicals getting released, and the result is the predictable feelings of alertness, wakefulness, and even a bit of euphoria.

Caffeine Boosts Brain-Derived Neurotrophic Factor (BDNF)

Brain-derived neurotrophic factor, or BDNF, is a protein released in your central nervous system. BDNF is responsible for keeping your billions of brain cells (neurons) strong and healthy. It also plays a role in neurogenesis — the creation of new neurons from existing stem cells.

BDNF can be thought of as a type of growth hormone of the brain, which makes it extremely important for brain development,the learning process, and memory. Research reveals that caffeine triggers the release of BDNF.

bdnf neural networks

Caffeine Affects Brain Network Connectivity

Neuroscience has long studied how individual neurons communicate with one another and has gained a sound understanding of the process. More recently studies have concentrated on the more complicated matter of how neurons act collectively in large-scale neural networks that affect the entire brain. These studies have discovered something that intuitively doesn’t seem to make sense. Cerebral entropy, or brain entropy — irregular variability in brain activity from one moment to another is a good thing.

This complexity and irregular variability in neuron activity is an indicator of greater information processing capacity. The opposite — periods of low entropy where repetition and orderliness are prevalent, as occurs during deep sleep — coincide with much less information processing. So it turns out that a messy brain is a good brain, to greatly simplify!

A 2018 study in Scientific Reports shows that caffeine causes an extensive, widespread increase in brain entropy — even when the brain isn’t actively engaged. The idea that caffeine increases information processing capacity even in the resting brain indicates that caffeine’s brain processing boost lasts well after you’ve finished your morning cup of coffee.

L-Theanine Has Cognitive-Enhancing Effects

L-theanine (chemical name N-ethyl-L-glutamine) is an amino acid present in the leaves of Camellia sinensis tea. Interestingly, both green and black tea are made from the same plant — Camellias sinensis (the color difference comes from how the tea leaves are processed). So whether a person drinks green or black tea, they’re ingesting some L-theanine.

L-theanine, or simply theanine, naturally induces feelings of relaxation and calmness, without causing drowsiness. That makes L-theanine beneficial for anyone who needs to stay stress-free and focused during intense, demanding cognitive tasks.

L-theanine is a nootropic because it’s known to improve several areas of cognition:

  • concentration
  • alertness
  • mood
  • focus
  • creativity

There are a few ways L-theanine acts to increase cognitive functions, as listed here.

L-Theanine Increases Alpha Brain Waves

Each of the human brain’s billions of neurons is connected to many other neurons in huge networks. Communication between neurons occurs by way of minute electrical currents that travel in waves from neuron to neuron. These brain waves (or brainwaves) carry information by the frequency of of their oscillation — their rate of repetition.

An oscillation is a cycle of movement from a starting point back to that same point. Think of a pendulum starting at one place, swinging, and returning to its starting location. That’s one oscillation, or cycle. The frequency of a wave is the number of oscillations the wave covers in one second. Frequency is measured in hertz (Hz), with one oscillation in one second being 1 Hz, two oscillations in one second being 2 Hz, and so forth.

Brain waves are categorized into five states, based on their wavelengths. Gamma (γ) brain waves have the highest frequency (short wavelengths generating more oscillations, or cycles, per second). This is the brain at its most active. At the other end of the spectrum are delta (δ) brain waves — they have the lowest frequency (long wavelengths generating fewer oscillations, or cycles, per second).

Near the middle of the brain wave frequency spectrum are alpha (α) brain waves. In terms of calm alertness and heightened creativity, alpha waves are considered the “sweet spot.” Alpha waves put a person in a state of awake relaxation, or “calm focus.” Your ability to focus is strong, you’re alert, and you’re feeling creative — but you’re still feeling pretty chill.

brainwaves l-theanine

Studies show that one of the ways L-theanine affects the brain is in its ability to trigger the release of alpha waves. In trials with both low-anxiety and high-anxiety participants given L-theanine supplementation, alpha brain waves in both groups increased within 30 minutes, fostering an alert but relaxed mental state in both groups.

L-Theanine Increases GABA Production

Neurotransmitters are molecules the nervous system uses to transmit chemical messages between neurons. Most types of neurotransmitters are excitatory neurotransmitter — they increase nervous system activity. An example of an excitatory neurotransmitter is adrenaline, which is increases glucose production, blood pressure, and heart rate — typically in response to a dangerous situation.

Some other neurotransmitters are inhibitory neurotransmitters because they inhibits (block) specific brain signals, decreasing nervous system activity. GABA (chemical name gamma-aminobutyric acid) is an example of an inhibitory neurotransmitter.

GABA blocks or slows specific nerve signals in the brain when you experience stress or anxiety in order to bring about a calming, relaxing effect. Sufficient GABA levels are so important that low levels may be associated with mood or anxiety disorders, and even chronic pain and epilepsy.

Studies show that L-theanine boosts GABA levels, bringing about a calmness that helps in studying and learning. The research demonstrates that L-theanine can also increase levels of the “happy” or “feel-good” neurotransmitters dopamine and serotonin.

L-Theanine Decreases Excitatory Neurotransmitters

You’ve just read that L-theanine increases the inhibitory neurotransmitter GABA which reduces stress. L-theanine also decreases some excitatory neurotransmitters, which also reduces stress. Stress has a decidedly negative effect on decision-making ability, as well as causes damage to neurons.

L-theanine can suppress the function of glutamatergic receptors, which lowers levels of glutamate, an excitatory neurotransmitter associated with stress and anxiety. L-theanine also decreases levels of the hormone corticosterone. High levels of corticosterone interfere with memory formation and learning.

The Synergy of Stacking Caffeine and L-Theanine

In the nutritional supplement world, stacking refers to identifying two or more nutrients that each target the same health concern, and then taking supplements of those nutrients together — you “stack” one supplement on another, so to speak. Each nutrient may provide benefit to the same health issue, but most likely each will do so in a slightly or significantly different way. Multiple nutrients complement one another, resulting in a more complete benefits package.

nootropic stacking hands

Nootropic supplement manufacturers of course know all about the concept of stacking, so you’ll find plenty of nootropic supplements that are combinations of multiple nootropics. This includes one of the most simple, popular, and inexpensive nootropic stacks — the pairing of caffeine and L-theanine. Pure Nootropics Caffeine + L-theanine is such a stack that’s available as a four-month supply for only about fifteen bucks.

purenootropics caffeine l-theanine

By themselves, both caffeine and L-theanine are each effective nootropics. When combined, though, there’s a distinct synergistic effect. When caffeine and L-theanine are taken in combination, expect to experience some or all of the following benefits.

  • Heightened awareness
  • Increased focus
  • Boosted learning ability
  • Faster reaction times
  • Increased accuracy
  • Enhanced memory recall
  • Improved multitasking abilities
  • Less anxiety

L-Theanine Counteracts Caffeine’s Negative Effects

Nootropically, caffeine provides many benefits, including increased focus, alertness, and memory recall. But for many people, caffeine also has some negatives: it can raise blood pressure, increase anxiety, or give a person a case of the “jitters.” Reducing or eliminating these caffeine cons is where L-theanine comes into play — when taken with caffeine, L-theanine takes the edge off of the caffeine.

Back a bit it was mentioned that one of the things L-theanine does is increase alpha waves, and that this type of brainwave accompanies states of relaxation. This boost in alpha brain waves helps reduce the restlessness that can accompany the taking of caffeine. L-theanine increases neurotransmitters such as GABA and dopamine, which can also contribute to a more relaxed state.

Caffeine is a vasoconstrictor — it temporarily causes a narrowing of blood vessels. Narrower blood vessels mean reduced blood flow and an increase in blood pressure. Regarding blood flow, L-theanine functions in an opposite manner. L-theanine increases vasodilation. Dilation means to make wider, larger, or more open. So L-theanine widens blood vessels, which lowers blood pressure.

Adding Theobromine to the Caffeine and L-Theanine Stack

While many people are content with the combination of caffeine and L-theanine, some nootropic-savvy folks like to up their game by adding a third brain-enhancer to the mix. Enter theobromine, a compound found primarily in cacao plants.

Like caffeine, theobromine is an adenosine antagonist — it blocks the accumulation of the calming neurochemical adenosine resulting in a stimulating effect. This makes sense, as chemically theobromine is in the same family as caffeine. The stimulating effect of theobromine, however, is much less than that of caffeine, so it doesn’t typically produce an edgy or jittery effect.

Chocolate, cocoa, and cacao products are all made from cacao beans, so when you eat a chocolate bar, you’re getting some theobromine. If eating chocolate gives you a bit of a euphoric feeling, you can thank theobromine for that. The calm, tranquil sense brought on by theobromine won’t make you tired, though. On the contrary, theobromine improves focus and alertness, which is its main claim to fame as a nootropic.

While theobromine is related to caffeine, it doesn’t share caffeine’s vasoconstrictor properties. In fact, when it comes to blood pressure theobromine acts much like L-theanine — it’s a vasodilator that expands blood vessels to lower blood pressure.

purenootropics 1-2-go

Taking Caffeine and L-Theanine Supplements

How you consume your daily dose of caffeine and L-theanine depends on whether or not you’re a coffee drinker.

Caffeine and L-Theanine Dosages

For the best nootropic results, caffeine and L-theanine should be taken together, in a ratio of 1:2. That is, one part caffeine with two parts L-theanine. A single dose of this combination is considered to be 100 mg of caffeine with 200 mg of L-theanine.

If you want to take your L-theanine without drinking coffee, then you should buy a supplement such as Caffeine + L-Theanine from Pure Nootropics (pictured earlier). One capsule of this supplement consists of 100 mg of caffeine and 200 mg of L-theanine — the perfect 1:2 ratio mentioned above.

For coffee drinkers, there’s no need to buy a supplement that includes both caffeine and L-theanine — you no doubt are getting plenty of caffeine from your daily java! Instead, opt for a supplement that includes only L-theanine, such as Now L-Theanine from A1 Supplements (pictured below). One capsule of this supplement consists of 100 mg of L-theanine, and no caffeine. Conveniently, a typical cup of coffee contains about 100 mg of caffeine — so you’d take two Now L-Theanine capsules along with your cup of coffee to consume the standard 1:2 ratio of caffeine to L-theanine.

a1supplements now l-theanine

How often can you take L-theanine? Interestingly, L-theanine has been demonstrated to have virtually no toxicity level and no chances of chemical dependency. With that said, it’s generally not a good idea to ingest a near-unlimited amount of any compound! One or two doses of 200 mg of L-theanine (a total of 200 mg to 400 mg) is a typical daily usage, though some people take up to four doses of 200 mg daily (a total of 800 mg).

While L-theanine seems to be well-tolerated at very high levels, the same can’t be said for caffeine. Up to 400 mg of caffeine daily seems to be very safe for most adults, though it’s difficult to name one exact amount that applies to everyone as people can have different reactions or sensitivities to caffeine based on tolerance, medical history, and age. That 400 mg figure represents about four average cups of coffee. Many people can well-tolerate six cups of coffee per day (600 mg of caffeine).

Caffeine and L-Theanine Side Effects

How well-tolerated caffeine is varies considerably from person to person. Some people can drink a half dozen cups of coffee in a day (600 mg of caffeine) with absolutely no side effects, while others feel restless, jittery, and anxious after just two cups in a day (200 mg of caffeine). People who do have issues with caffeine usually experience one or more of the following negative effects:

  • Insomnia
  • Restlessness
  • Headaches
  • Dizziness
  • Rapid heart rhythm

If you become a fan of L-theanine you’ll be very happy to hear that in addition to there being no known upper limit on dosages, side effects of any kind are exceedingly rare. When side effects do occur they tend to be very mild (headaches) and come only at very high L-theanine dosages (over 1,500 mg daily).


Coffee gives you a boost of energy, but it also gives you a mental boost. The caffeine in coffee is a nootropic — a compound that provides cognitive-enhancing effects. Caffeine has a downside, though — many coffee drinkers experience nervousness, jitteriness, or anxiousness. To counter these negatives, consider supplementing your caffeine intake with another nootropic — L-theanine.

L-theanine is an amino acid that’s present in the leaves of green and black tea. Tea leaves contain L-theanine, but not in sufficient quantities to be especially useful as a nootropic. Because of this most people who want to up their L-theanine intake do so by taking L-theanine supplements.

Being a nootropic, L-theanine provides brain-enhancing benefits such as improved focus. It can work synergistically with caffeine, significantly improving caffeine’s positive mental effects. Equally important, though, is the ability of L-theanine to provide a calming effect that prevents caffeine’s jitters without taking away from the alertness buzz people enjoy and expect from caffeine.