L-theanine (N-ethyl-L-glutamine) or theanine is a major amino acid uniquely found in green tea. 

Research indicates that L-theanine promotes relaxation without drowsiness. Promoting a feeling best described as “Zenergy” whereby there is a sensation of energy with control - so you are focussed with mental clarity.

L Theanine is highly synergistic with caffeine whereby it can “reduce the side-effects of caffeine” while increasing the benefits of caffeine. There is a pronounced synergistic effect. This means you experience heightened focus, awareness, and energy, as well as reduced stress, healthy vascular function and improved mental endurance at higher levels.

 L-theanine Fast Facts

  • L-theanine promotes feelings of “zenergy” - being calm, attentive and focused
  • Increases blood flow to the brain - leading to an increase of cognitive function and positive mood
  • Improves attention and alertness with resilience to distractions
  • Removes the jitters and other side effects of caffeine

L-Theanine as an active ingredient of Savvy

Amount used: 200mg

Active ingredient: L-Theanine

Why: 200mg of l-theanine is the perfect dose according to science to have a very beneficial effect on adults when paired in a 2:1 ratio with caffeine. L theanine and caffeine work very well together and this is why it has been added to Savvy.

Main benefits for Savvy

  • Promotes feelings of “zenergy” - being calm, attentive and focussed
  • Increased blood flow to the brain leading to an increase of cognitive function and positive mood
  • Improved attention and alertness with resilience to distractions
Scientific Benefits of L-theanine

To make it easy to identify all the different studies - we will highlight them for you!

We really hope you enjoy our many years of research when formulating Savvy...

Benefit 1: L-theanine promotes feelings of “zenergy” - being calm, attentive and focused

L-theanine promotes zenergy and focus


Nathan, PJ, et al, ‘The neuropharmacology of L-theanine(N-ethyl-L-glutamine): a possible neuroprotective and cognitive enhancing agent.’ in Journal of herbal pharmacotherapy, Volume 6, Issue 2, 2006, pp 21 - 30 [Link]


“L-theanine (N-ethyl-L-glutamine) or theanine is a major amino acid uniquely found in green tea. L-theanine has been historically reported as a relaxing agent, prompting scientific research on its pharmacology. Animal neurochemistry studies suggest that L-theanine increases brain serotonin, dopamine, GABA levels and has micromolar affinities for AMPA, Kainate and NMDA receptors. In addition has been shown to exert neuroprotective effects in animal models possibly through its antagonistic effects on group 1 metabotrophic glutamate receptors. Behavioural studies in animals suggest improvement in learning and memory. Overall, L-theanine displays a neuropharmacology suggestive of a possible neuroprotective and cognitive enhancing agent...”


Nobre, AC, et al. ‘L-theanine, a natural constituent in tea, and its effect on mental state’ in Asia Pacific journal of clinical nutrition, Volume 17, Supplement 1, 2008, pp 167-168. [Link


“tea also contains a unique amino acid, L-theanine that may modulate aspects of brain function in humans… L-theanine significantly increases activity in the alpha frequency band which indicates that it relaxes the mind without inducing drowsiness…”


Haskell, CF, et al, ‘The effects of L-theanine, caffeine and their combination on cognition and mood.’ in Biological psychology, Volume 77, Issue 2, February 2008. PP 113 - 122. [Link


“the combination also led to faster simple reaction time, faster numeric working memory reaction time and improved sentence verification accuracy. 'Headache' and 'tired' ratings were reduced and 'alert' ratings increased. There was also a significant positive caffeine x L-theanine interaction on delayed word recognition reaction time. These results suggest that beverages containing L-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone.”


Camfield, DA, et al, ‘Acute effects of tea constituents L-theanine, caffeine, and epigallocatechin gallate on cognitive function and mood: a systematic review and meta-analysis.’ in Nutrition reviews, Volume 72, Issue 8, August 2014, pp 507 - 522. [Link]


“A systematic review and meta-analysis was conducted on 11 randomized placebo-controlled human studies of acute effects of tea constituents L-theanine and epigallocatechin gallate, administered alone or in combination with caffeine, on cognitive function and mood. The outcome measures of mood were alertness, calmness, and contentedness, derived from the Bond-Lader scales, and state anxiety, from the State-Trait Anxiety Inventory. Cognitive measures assessed were attentional switch, intersensory attention, and rapid visual information processing. Standardized mean differences between placebo and treatment groups are presented for each study and outcome measure. Meta-analysis using a random-effects model was conducted when data were available for three or more studies. Evidence of moderate effect sizes in favor of combined caffeine and L-theanine in the first 2 hours postdose were found for outcome measures Bond-Lader alertness, attentional switching accuracy, and, to a lesser extent, some unisensory and multisensory attentional outcomes. Moderator analysis of caffeine and L-theanine doses revealed trends toward greater change in effect size for caffeine dose than for L-theanine dose, particularly during the first hour postdose.”


Nobre, AC, et al, ‘L-theanine, a natural constituent in tea, and its effect on mental state.’ in Asia Pacific journal of clinical nutrition, Volume 17, Supplement 1, 2008 pp 167 - 168. [Link]


“L-theanine significantly increases activity in the alpha frequency band which indicates that it relaxes the mind without inducing drowsiness...These data indicate that L-theanine, at realistic dietary levels, has a significant effect on the general state of mental alertness or arousal. Furthermore, alpha activity is known to play an important role in critical aspects of attention.”

Benefit 2: L-theanine increases blood flow to the brain - leading to an increase of cognitive function and positive mood

L-theanine improves cognitive function and mood


Dodd, FL, ‘A double-blind, placebo-controlled study evaluating the effects of caffeine and L-theanine both alone and in combination on cerebral blood flow, cognition and mood.’ in Psychopharmacology (Berl), Volume 232, Issue 14, July 2015, pp 2563 - 2576. [Link]


“Caffeine reduced oxygenated haemoglobin (oxy-Hb), increased deoxygenated haemoglobin (deoxy-Hb), improved performance on attention tasks and increased overall mood ratings….Combining L-theanine with caffeine, at levels and ratios equivalent to one to two cups of tea, eliminated the vasoconstrictive effect and behavioural effects of caffeine. This supports previous findings of an interaction between these substances.”


Satarupa, D, ‘Neuroprotective attributes of L-theanine, a bioactive amino acid of tea, and its potential role in Parkinson's disease therapeutics’ in Neurochemistry International, Volume 129, October 2019 [Link]


This unique amino acid also bears a potential to ameliorate the pathophysiological changes associated with Parkinson's disease as it displays antioxidant and anti-inflammatory properties, improves motor behavioral abnormalities, increases dopamine availability and may cause a favorable downshift in neurodegeneration due to glutamate excitotoxicity.

Benefit 3: L-theanine improves attention and alertness with resilience to distractions

L-theanine improves focus and attention


Kelly, SP, ‘L-theanine and caffeine in combination affect human cognition as evidenced by oscillatory alpha-band activity and attention task performance.’ in The Journal of nutrition, Volume 138, Issue 8, August 2008, pp 1572S - 1577S [Link]


“Recent neuropharmacological research has suggested that certain constituents of tea may have modulatory effects on brain state...This may signify a more generalized tonic deployment of attentional resources to the visual modality and may underlie the facilitated behavioral performance on the combined ingestion of these 2 major constituents of tea.”


Owen, GN, et al, ‘The combined effects of L-theanine and caffeine on cognitive performance and mood.’ in Nutritional neuroscience, Volume 11, Issue 4, August 2008, pp 193 - 198. [Link]


“The L-theanine and caffeine combination improved both speed and accuracy of performance of the attention-switching task at 60 min, and reduced susceptibility to distracting information in the memory task at both 60 min and 90 min. These results replicate previous evidence which suggests that L-theanine and caffeine in combination are beneficial for improving performance on cognitively demanding tasks.”

Park, SK, et al, ‘A combination of green tea extract and l-theanine improves memory and attention in subjects with mild cognitive impairment: a double-blind placebo-controlled study.’ in Journal of medicinal food, Volume 14, Issue 4, pp 334 - 343. [Link]

“Brain theta waves, an indicator of cognitive alertness, were increased significantly in the temporal, frontal, parietal, and occipital areas after 3 hours in the eye-open and reading states. Therefore, this study suggests that [GTE and L-Theanine] LGNC-07 has potential as an intervention for cognitive improvement.”


Based on studies like those listed above, Savvy Beverages developed Savvy Brain Boost to boost brain function. It’s a delicious beverage with amazing added supplements for daily use to provide long-lasting mental energy, support brain function and enhance cognitive performance.

Each delicious Savvy Coffee provides a clinical dose of many nootropics including L-Theanine (above), to decrease stress and fatigue while boosting focus and improving mood. Savvy also provides complementary herbs, amino acids, vitamins, and minerals with high levels of evidence for cognitive enhancement.