6 Fantastic Benefits Of L-Theanine For Boosting Memory

L-theanine for memory boost

Name: L-theanine, γ-glutamylethylamide
Goes well with: Green tea catechins, Caffeine
Number of scientific references: 35
Level of Evidence: Level III What is this?

Note:L-theanine present in green tea has excellent relaxing and anti-stress properties. It is proven to enhance memory, cognition and attention in humans. Many studies have found its combination with caffeine very effective as a cognition enhancer but more research is required about the safety of this duo.

The interesting feature about natural memory boosters is that they do more than just boosting our memory. Some may strengthen your cognitive skills, some may boost antioxidant power, some may even reduce the risk of neurodegenerative disorders in addition to sharpening the memory etc.

Green tea is touted as one of the healthiest beverages around. It isn’t surprising that tea is the most consumed beverage after water. Green tea helps relax, it boosts antioxidant defences, it is useful for many health conditions, and it can aid in detox.

Green tea can aid in mitigating the cause behind memory lapse (if not limited by its low bioavailability); it also contains one ingredient that boosts cognition and memory. I am talking about L-theanine, though caffeine and green tea catechins also protect cognition.

L-theanine or γ-glutamylethylamide is a non-protein amino acid that is present in Camellia sp. (tea family) and bay boletes mushroom Xerocomus badius. It is a rare amino acid as these two are its only natural sources.

L-theanine constitutes 1-2% of dry weight of tea, so you get around 25-60mg per 200ml of the tea. It contributes to the taste of the tea, hence tea with high amounts of theanine is priced higher.

Various factors dictate the level of theanine in the tea but particularly Camelia sinensis var sinensis is said to have high concentrations of the amino acid.

L-theanine is known to cross the blood-brain barrier within 30 minutes and produces a relaxing feeling within 40-60 minutes of consumption. Quite a bit of research shows that it stimulates alpha wave production to increase alertness. These properties of this rare amino acid can help boost attention and memory.

Let’s explore the benefits of L-theanine for memory enhancement.

Suggested L-Theanine Supplements For Memory

Please consult a health practitioner before taking any health supplement.

Apart from conventional L-theanine supplements, there are Suntheanine® supplements available. Suntheanine® is a patented form of L-Theanine produced by Taiyo International, Inc., Japan.

The company states that Suntheanine® is not an extract of green tea but produced via a fermentation process that mimics the natural process of L-theanine production in green tea leaves and gives pure L-theanine.As far as the effects are concerned, both are found to be equally effective by users. Cost differences exist.

If not supplements, you may consider buying L-theanine powder or liquid extract that you can add to your juices.

I have listed a few L-theanine and Suntheanine® supplements below which users have reported to be beneficial for memory.

Source Naturals L-Theanine Sports Research L-Theanine Doctor’s Best L-Theanine
200mg L-theanine in vegetable capsules 250mg Suntheanine and coconut oil in gelatin softgel capsules 150mg Suntheanine in vegetable capsules
Buy from Amazon (US, UK, Canada)

Buy from iHerb (Global)

Buy from Amazon (US, UK, Canada)

Buy from iHerb (Global)

Buy from Amazon (US, UK, Canada)

Buy from iHerb (Global)

6 Fantastic Benefits of L-theanine For Boosting Memory

L-theanine’s unique therapeutic activity makes it an excellent natural agent for stress relief and improved memory and focus.

1. L-theanine protects memory and cognition

Age-related changes in brain structure and function vary with every individual and are not uniform even throughout the whole brain. But, the most common cognitive parameters affected by ageing are memory and attention.

Engaging in cognition stimulating activities can delay the onset of dementia. A study published in Neurology, 2009 reported that each additional day of cognitive activity helped delay onset of increasing memory decline by 0.18 years.

Including cognition enhancing foods in your diet can’t replace the benefits of participating in cognitive activities, but the combination can boost your mental well being.

Theanine is one such cognition enhancing food. Its chemical structure is similar to that of glutamate, a chemical in the brain that is involved in developing memories.

Theanine crosses the blood-brain barrier and helps to protect neurons from cell death and injury. The experimental study suggests that theanine can contribute to the development of the hippocampus- the part of our brain that is involved in storing memories.

Its intake increases the levels of nerve growth factors and proteins like Brain-Derived Neurotrophic Factor specifically in the hippocampus.

This in turn promotes the development of neurons in this area and strengthens our neural connections. It is also found to improve our ability to recognise previously encountered objects, people or events.

Theanine is found to regulate various neurotransmitter levels which may throw some light on its ability to strengthen memory and learning.

Researchers observed that elderly individuals who consumed green tea powder enriched with L-theanine (47.5mg theanine per day) had reduced cognitive decline.

Matcha tea is a trending superfood these days, and its constituents L-theanine, epigallocatechin gallate and caffeine can help boost mood and cognition.

A study published in Food Research International, 2017 explored the benefits of matcha tea, as a drink or snack bar, on cognition . 23 individuals were enrolled in the study and were asked to consume either matcha tea or matcha snack bar or placebo tea or placebo bar.

Various tests were conducted at baseline and 1 hour after consumption of the products. The matcha products contained about 4g matcha tea powder.

An improvement in attention and reaction was observed with matcha consumption. But no significant changes in mood were observed.

Consumption of matcha tea was found to improve cognitive performance better than the snack bar enriched with matcha powder; particularly working memory speed.

Overall, single serving of matcha tea brought about slight improvements in attention and memory.

Quick Gist: L-theanine is found to strengthen memory and cognition by regulating various neurotransmitters and increasing the growth and development of neurons in the part of the brain that deals with memory retention.

Green tea and matcha tea are great sources of L-theanine that can help boost and protect cognition.

2.It protects from stress-induced memory decline

Cortisol is known as the stress hormone. Alteration in cortisol levels can impair retrieval of memory, and in mental health disorders, it may even cause dysfunction in parts of the brain dealing with memory.

Animal studies suggest that theanine administration helps to protect memory even under stressful conditions. This activity of the amino acid is attributed to the property of reducing stress hormones as well as improving neural connections in areas of memory retention.

Japanese researchers have found that L-theanine consumption exerts an anti-stress action in humans. This was evidenced by reduction of heart rate and reduced activation of our flight-or-fight response system in the face of acute stress.

A study published in Nutrients, 2016 highlighted the effects of L-theanine drink on stress response. 34 healthy individuals participated in the study, and they were given a nutrient drink containing 200mg L-theanine.

Within 1 hour of consumption of the nutrient drink, a reduction in stress response was observed. Cortisol levels in the saliva reduced within 3 hours of consumption. An increase in alpha wave activity (indicating a state of calmness and relaxation) was observed in those with high anxiety.

Apart from anti-stress activity, L-theanine also possesses anti-depressant property.

Chronic L-theanine administration (250mg per day)for eight weeks is proven to reduce depressive symptoms, anxiety, sleep disturbances and cognitive impairment in patients with the major depressive disorder.

Quick Gist: L-theanine’s anti-depressant and anti-stress property can help protect from stress-induced memory impairment. A dose of 200-250mg of L-theanine helps alleviate stress-related symptoms.

3.It is a neuroprotective agent

Neuroprotection helps strengthen the activity of the central nervous system, and this translates into better cognitive function and memory.

Theanine has proven neuroprotective effects that it mediates by :
• Regulating various chemicals in the brain
• Exerting a calming effect and reducing anxiety
• Protecting from and supporting recovery in case of brain injury
• Improving attention, memory and learning
• Benefiting in mental health disorders such as depression and schizophrenia

Theanine’s structure is similar to that of glutamate, a neurotransmitter that regulates various functions in the body including memory.

However, researchers state that the amino acid’s neuroprotective action may not be limited to this mechanism alone.

Apart from glutamate, theanine also increases the levels of neurotransmitters (chemicals in the brain that are involved in our mood) serotonin and dopamine to protect brain health and enhances cognition.

Beyond regulating neurochemistry, L-theanine also protects the brain from neurotoxicity. A group of Korean researchers have proven that the amino acid elevates factors that help neurons survive and protects the brain from neurotoxic insults.

L-theanine reduces the levels of inflammatory agents and boosted antioxidant defences to counteract the adverse effects of the toxins.

Exposure to heavy metals such as cadmium can impair memory and contribute to the development of neurodegenerative diseases. A study published in Neurotoxicology, 2016 revealed that L-theanine helps elevate antioxidant enzymes and protects brain cells from cadmium exposure.

The study also showed that cadmium exposure could initiate certain changes in the brain such as unhealthy accumulation of proteins. This could lead to the formation of neurodegenerative diseases such as Alzheimer’s and dementia.

Interestingly L-theanine interrupts this process and prevents it from progressing into degenerative diseases of the brain.

Quick Gist: L-theanine helps to protect the brain by regulating brain chemistry, boosting antioxidant power, reducing inflammation and counteracting adverse effects of toxin exposure. These activities strengthen brain health and indirectly boost memory and cognition.

4. L-theanine prevents memory decline and halts early stages of dementia

L-theanine shows therapeutic properties for neurodegenerative diseases. It can help protect memory and cognitive decline and can aid in the prevention of such diseases.

In an experimental model of Alzheimer’s disease, L-theanine was found to reduce amyloid beta plaque levels and improved antioxidant defences of the brain. Amyloid beta protein is abnormally expressed and accumulated in the brain in Alzheimer’s.

Researchers state that L-theanine can help in prevention and treatment of Alzheimer’s disease.

Aluminium exposure can increase the risk of developing Alzheimer’s disease. L-theanine’s antioxidant property can help prevent aluminium induced toxicity in the brain.

Mild cognitive impairment is a stage where an individual’s cognitive function is impaired in comparison to that of a healthy counterpart and is at the risk of worsening and progressing into dementia or Alzheimer’s.

Park et al. demonstrated via their clinical study that a combination of green tea extract and L-theanine can benefit in mild cognitive impairment.

91 patients enrolled in the study took either 1680mg of the green tea and L-theanine or placebo for 16 weeks. The combination therapy was found to improve memory and attention.

The therapy also increased the level of brain theta activity indicating an increase in alertness. Green tea and L-theanine successfully aided in improving cognition in mild cognitive impairment patients.

Quick Gist: Research shows that L-theanine can aid in prevention and treatment of Alzheimer’s disease. Combination of green tea extract and L-theanine is proven to prevent cognitive decline and strengthen memory in mild cognitive impairment.

5. It may help support neurogenesis

Neurogenesis is the formation of new neurons or brain cells. Earlier it was thought that our brain stops growing after a certain stage, but today we have learned that we do develop new neurons in some parts of the brain in adulthood. This is known as adult neurogenesis.

Scientists have found that adult neurogenesis plays an important role in memory retention and updating stored memories.

Theanine helps promote neurogenesis by activating biochemical pathways related to it. Its structural similarity with L-glutamine helps contribute to this activity.

Takeda et al., in their animal study, proved that theanine administration helped increase neurogenesis in the part of the brain that deals with memory formation and retention. As a result, this led to memory enhancement under experimental settings.

Quick Gist: Adult neurogenesis or formation of new neurons in adulthood, is involved in memory storage. Theanine is proven to support neurogenesis, and this can aid in boosting memory.

6. L-theanine and caffeine boost memory and cognition

Various resources list that the combination of L-theanine and caffeine works as a nootropic.

Kelly et al. proved that this combination increases memory and attention and this was evidenced by a change in alpha waves of the brain. The dose used was 100mg L-theanine and 50mg caffeine alone or in combination.

Researchers felt that L-theanine can improve attention when taken alone at high doses or if taken in small doses with caffeine.

Increase in alertness, accuracy and speed in a task involving attention and better performance in memory tasks is observed with 100mg L-theanine and 50mg caffeine combination.

Haskell et al. examined the effects of high dose caffeine (150mg) and L-theanine (250mg) on cognition. L-theanine alone at high dose increased headache.

But the combination reduced mental fatigue, headaches, increased alertness and reduced reaction time in simple as well as memory-related tasks.

Contrary to expectations, a recent study published in Psychopharmacology, 2015 demonstrated that but the combination did not benefit cognition at the given dose.

But l-theanine, when taken with caffeine, helped to attenuate the ‘reduced blood flow to the brain’ effect caused by caffeine.

The dose tested was 75 mg caffeine and 50mg L-theanine which is similar to what one would get after consuming 1-2 cups of tea.

However, the researchers did comment that though their results, at the given dose, do not support the earlier findings the case with tea consumption is entirely different.

Tea would have much more bioactive compounds that would interact with the duo and deliver a different effect.

Quick Gist: The combination of L-theanine (100mg) and caffeine (50mg) is proven to improve memory, cognition and attention. However, this effect is dose-dependent and needs more research to confirm their long term safety.

Researchers hypothesise that when this duo is taken as part of tea other bioactive agents present in tea may alter caffeine-theanine’s action and deliver a beneficial effect on memory and cognition.

Dosage of L-theanine For Boosting Memory

There is no prescribed dosage of L-theanine for boosting memory. As per the studies, a dose of 100mg L-theanine is successful in strengthen memory and increasing focus.

In case of stress, depression or anxiety is the cause for memory deficit a dose of 200-250mg l-theanine is found to benefit in such cases.

If not looking forward to supplements, you can also opt for l-theanine enriched food products. You can also buy L-theanine powder or liquid extract that you can add to your juices and smoothies.

Consuming 1-2 cups of green tea every day can provide you with a healthy dose of L-theanine, but it may not be sufficient in case of serious memory lapses or health conditions involving cognitive decline.

A study published in The Journal of Nutrition, 2012 reported that L-theanine is rapidly absorbed from both supplements as well as green tea. Its metabolism and excretion are similar in both cases: supplements or tea.

Please consult a health practitioner before taking l-theanine supplements.

Precautions with L-theanine Use

L-theanine is found to be safe if taken in recommended doses. Always start with small doses and scale up gradually.

A dose of 100mg works fine for most individuals. Higher doses may cause headaches, dizziness and gastric discomfort in some.

It’s combination with caffeine is found to counteract adverse effects of caffeine but only when taken at right doses. More research is required to confirm their safety.

Some studies have evaluated the effect of L-theanine in combination with psychiatric medications, and no side effects have been reported. But it is best to keep a 3-4 hour gap between the two and consult a health practitioner before taking the combination.

Not much is known about L-theanine’s interaction with other drugs. Please consult your doctor before taking L-theanine supplements.


L-theanine is one of the components that makes tea a relaxing potion. This amino acid is rare and not found in the diet.

It helps regulate neurotransmitter levels, boosts antioxidant power, exerts a neuroprotective effect and protects the brain from toxins. Combination of these therapeutic properties makes theanine an effective natural memory booster.

It’s in combination with green tea extract is proven to strengthen memory in case of mild cognitive impairment. Theanine supplementation alone is proven to improve cognition and memory in healthy individuals as well.

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Know the proven benefits and dosage of L-theanine for boosting memory.




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