Theanine (L-theanine) is a powerful neuroenhancer often heralded as a relaxation enhancing tool similar to meditation. The compound improves alpha brain waves, which is a pattern in the brain correlated with the highest activity and mental capacity .
Beyond these benefits, theanine is helping improve upon the positive aspects of caffeine while mitigating the negative issues such as anxiety, increased blood pressure, and diminished sleep quality . Theanine has also been found to have positive effects on brain chemistry .
Other Common Names
Supports cognitive function
Supports relaxed mood
Supports stress resilience
Supports general immune health
What Is Theanine?
Theanine is one of the most ubiquitous compounds that few people are aware they ingest. As a main psychoactive constituent of tea leaves, this amino acid has been improving brain health for thousands of years across the globe. According to studies in the past few decades, this specific nonessential amino acid is one of the most useful tools for people using smart drugs.
Theanine is a calming amino acid that naturally occurs in green tea. It is used as a smart drug because it supports focused attention, mental alertness, and a calm, relaxed sense of mental energy. Theanine is often used with caffeine because the combination supports task switching, accuracy, and focus. However, theanine is entirely effective on its own, especially as a stress adaptogen (reducing adverse effects of stress on the body). Theanine promotes alpha brain waves (α-waves), which are thought of as a marker of relaxation . This brain state also reduces the perception of stress. Theanine has a few other lesser-known functional actions. Theanine can be broken down into glutamate, which is a building block for glutamatergic signaling, i.e., the glutamate-GABA pathway, and for glutathione, an antioxidant used for detoxification. Theanine, because of another metabolite, primes specialized immune cells—gamma delta T cells—that help the immune system respond more efficiently to new antigens and have enhanced immune memory. The best dietary sources of theanine are green and black tea (made from Camellia sinensis). Theanine comprises up to 50% of total amino acids in tea leaves.
Marco’s Grounds Theanine Sourcing
Our theanine is extracted from organic green tea leaves. Marco’s Grounds theanine is sourced from family-owned organic farms and is non-GMO, gluten-free, and vegan.
Theanine Dosing Principles and Rationale
Theanine has been studied clinically over a relatively wide range of doses, with the most common range being 100-400 mg. Evidence suggests a threshold response (see Marco’s Grounds Dosing Philosophy) when theanine is given by itself, i.e., the best responses occur when it’s dosed within a range as opposed to more being better. That said, the dose of theanine used in Marco’s Grounds was based on assuming the user also drinks three to four coffees a day (upper scale of users). Thus, the formulation was calibrated to provide soothing effects with these quantities of caffeine in mind. Theanine tends to work perfectly when put in a ratio of 2:1 compared to caffeine or theobromine. When used in combination with GABA before bedtime for supporting sleep, it might be dosed at as little as 20% of the GABA dose, i.e., 1:5 ratio. Following an oral dose, the amount of theanine in the brain increase within the first hour, i.e., it’s able to cross the blood-brain barrier , so in general, theanine has a relatively quick onset. It is often experienced within 30-45 minutes of ingestion. Shall the user not drink coffee or ingest caffeine sources, theanine still works as a stress reducer and focus increaser.
Theanine Key Mechanisms
Supports attention [3–5]
Supports memory [6–9]
Supports learning 
Supports executive function [6, 11]
Supports faster reaction times 
Supports alpha brain waves (α-waves are associated with relaxation, selective attention, and mental alertness) [3, 5, 12–15]
Supports hippocampal activity 
Supports dopamine signaling [17–23]
Supports serotonin signaling 
Supports GABA levels in the brain 
Binds to glutamate receptors (with low affinity)[24–26]
Supports hippocampal neurogenesis 
Supports brain-derived neurotrophic factor (BDNF) [8, 26, 27]
Supports neuroprotective functions[9, 10, 28–30]
Mood and stress
Supports a calm/relaxed mood [6, 10, 11, 15, 16, 31–33]
Supports a positive mental-emotional bias [6, 11]
Modulates psychological and physiological stress responses 
Supports healthy behavioral and cognitive responses to stress [28, 36]
Reduces fight or flight nervous system activity (i.e., promotes relaxation response) 
Supports sleep efficiency and quality [6, 11, 37, 38]
Counters some of caffeine’s effects on deep sleep 
Supports innate immunity [40–42]
Supports adaptive immunity [40, 41, 42]
Supports gamma delta T cell function [44, 45]
Modulates immune signaling [40, 42]
Supports gut microbiota 
Supports amino acid absorption 
Healthy aging and longevity
Pro-longevity (Caenorhabditis elegans) 
Caffeine in cognitive performance [50–52]
GABA for supporting sleep quality 
L-Cysteine in support of general immune health [55–561]
Green tea extracts in support of general immune health [62, 63]
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