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L-Theanine Dietary Supplement
L-Theanine Unlock Your Potential
L-Theanine Supplement Facts
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L-Theanine Capsules

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L-theanine is an amino acid found most commonly in tea leaves and in small amounts in Bay Bolete mushrooms. It can be found in both green and black tea.

Research suggests that L-theanine might provide a range of health benefits, which may include improved mental focus and better sleep quality.

L-Theanine Benefits 

  • Increase mental focus 
  • Improve Sleep 
  • Provide relaxation
  • Increase cognitive performance 
  • It has neuroprotective effects 
  • Contributes to Weight loss
  • Boost the immune system 
  • Lowers blood pressure 
  • Anxiety and stress-relief 
  • May treat and prevent cancer 
  • Help treat the symptoms of sinusitis 
  • Increases Alpha brain waves 

L-Theanine promotes sleep quality due to its ability to provide relaxation by increasing alpha-brain waves and regulating excitatory neurotransmitters that may inhibit restful sleep.  Alpha brain waves (8-13 Hz) are the brain waves associated with relaxation and alertness and are produced within 30-40 minutes after ingestion.  The alpha-brain waves (or “a-waves”) occur in the occipital and parietal regions of the brain and prepare the body for a relaxed state prior to sleep.

L-Theanine may regulate stress levels by modulating the sympathetic nervous system when faced with an acute stressor by reducing heart rate and salivary stress immunoglobin A, leading to anti-stress effects.

Combined with caffeine, L-Theanine may improve performance on cognitively demanding tasks through its synergistic effects.  L-Theanine may help control blood pressure and may lessen some of the unwanted effects of caffeine.

Product Description

L-Theanine is a nootropic found in tea leaves that promotes relaxation and sleep and can be combined with caffeine for improved cognitive performance and focus.

L-Theanine is an amino acid that naturally occurs in tea leaves and some forms of mushrooms.  Tea (Camellia sinensis) contains 1-3% of L-theanine. It is used in a supplemental form isolated directly from tea leaves or prepared via chemical synthesis or biosynthesis. Green, black, oolong and white tea all contain L-Theanine in varying amounts.  Green tea and black tea contain the highest amounts of L-theanine, but the studies are conflicted about which of the two has the most.

L-Theanine Mode of Action

L-Theanine is absorbed through the intestines and reaches the blood-brain barrier in approximately 50 minutes after ingestion, similarly to the absorption through natural tea leaves.  L-Theanine can be found in the brain in the hippocampus after ingestion–the area of the brain responsible for learning and memory.

Research in animals suggests that L-Theanine (L-gamma-glutamyl-ethyl amide) works through glutamate receptors and increases levels of GABA and glycine in the brain, which causes relaxation. Increased GABA and glycine may increase serotonin and dopamine; however, it has also been noted that theanine may decrease or inhibit serotonin synthesis.

L-Theanine reduces glutamate release, an excitatory neurotransmitter.

L-Theanine Chemical Properties

Due to the large demand for L-Theanine supplements since its discovery in Japan in 1949, and its relatively low content in dry tea leaves–only about 1-2.5%, large scale productions are primarily responsible for the L-Theanine available in supplemental form.

Theanine has two isomers (or forms):  L-Theanine and D-Theanine. L-Theanine is the only form of Theanine found in tea and is the best form because it has the highest absorption capacity.  When Theanine is produced synthetically, either via chemical synthesis or biosynthesis, both isomers are produced.  The “L” form is approximately three times higher in the absorption level than the “D” form.  D-Theanine is not naturally occurring in foods.   If they are administered together, they can exhibit mutual antagonism and the “D” form can prevent the “L” form from being absorbed in the body.  It is not clear if the “D” form provides the benefits the “L” form is so widely used for so it is essential to know the purity of the supplement you are using.

L-Theanine Capsules & Dosage

L-Theanine Capsules provides an extra strength dose of 200 mg per capsule. 

Suggested use for adults is up to 2 capsules by mouth daily, or as directed by your healthcare practitioner.  Daily use may reduce efficacy.

The cognitive benefits associated with caffeine in combination with L-Theanine were studied on 50 mg caffeine to 100 mg L-Theanine, so we recommend caffeine to L-Theanine ratio should be 1-part caffeine to 2 parts L-Theanine.

L-Theanine Side Effects & Toxicity

L-Theanine, regardless of chemical synthesis, biosynthesis, or naturally occurring, is General Recognized As Safe (GRAS) by U.S. FDA.

L-Theanine is very well tolerated and side effects may include headaches and increased sleepiness.

Please contact your healthcare practitioner before supplementing L-theanine if you are taking any medications, herbs, or supplements. Note:  Due to L-Theanine’s effects on reducing blood pressure, possible interactions with pharmaceutical blood pressure medications, and herbs/supplements that may occur.

L-Theanine may reduce the effects of caffeine and mask the symptoms of taking too much caffeine.  These include the effects of energy drinks, coffee, black tea, oolong tea, guarana, mate, cola, and others.  Please be aware of your caffeine consumption during supplementation with L-Theanine.