L-Theanine

• CAS: 3081-61-1
• Catalog Number: ACM3081611
• Category: Other Products
• Molecular Weight: 36.46094;g/mol
• Molecular Formula: ClH
• Synonyms: (S)-2-Amino-5-(ethylamino)-5-oxopentanoic acid; L-γ-Glutamylethylamide; Nγ-Ethyl-L-glutamine; L-Glutamic acid γ-(ethylamide); L-Theanine; N(5)-ethyl-L-glutamine; THEANINE,L; SUNTHEANINE; N-γ-Ethyl-L-glutamine; N-Ethyl-L-glutamine
• IUPAC Name: chlorane
• SMILES: Cl
• InChI Key: VEXZGXHMUGYJMC-UHFFFAOYSA-N
• Boiling Point: 427.1ºC at 760 mmHg
• Melting Point: 207ºC
• Flash Point: 212.1ºC
• Density: 1.171 g/cm³
• Appearance: White Crystalline Solid
• EC Number: 231-595-7
• Exact Mass: 174.10000
• Hazard Statements: Xi:Irritant
• Safety Description: S28-S36/37
• UN Number: 1050

Case Study

L-Theanine as a Glutamate Analogue Anxiolytic for the Alleviation of Stress and Anxiety

Wang, Liwen, et al. Food Science and Human Wellness 11.3 (2022): 467-475.

L-Theanine, a non-protein amino acid present in tea leaves, acts as a structural analogue of glutamate that competes for glutamatergic receptors and crosses the blood-brain barrier, producing relaxation and anxiolytic effects relevant to functional food and nutraceutical applications.
Experimental Protocol: The compound is evaluated in rodent models through drinking water administration at concentrations from 5 to 100 ug/mL over 2 to 21 days, including chronic unpredictable mild stress protocols. Human trials use oral doses of 200 to 400 mg per day in randomized placebo-controlled designs. Outcomes include psychometric questionnaires and physiological markers such as heart rate, blood pressure and salivary enzyme activity.
Performance Evaluation: In rats, the compound releases striatal dopamine up to 300% of the basal value and improves open field, sucrose preference and forced swim measures with P below 0.001. In humans, 200 mg decreases heart rate, blood pressure responses and tension anxiety scores compared with placebo, while 400 mg per day lowers salivary amylase activity with P equal to 0.032. Bioavailability reaches 47% to 54%, and an LD50 above 5000 mg/kg demonstrates a wide safety margin. The compound also contributes to the umami taste of tea at a threshold of 24.0 mmol/L.

L-Theanine as a Dietary Supplement for the Support of Sleep Quality in Adults

Cotter, Jack, et al. Nutritional Neuroscience 29.2 (2026): 224-238.

L-Theanine functions as a naturally occurring amino acid supplement that supports healthy sleep in adults, acting through relaxation and modulation of inhibitory neurotransmission without causing sedation or cognitive impairment.
Experimental Protocol: A systematic review following PRISMA guidelines screens five electronic databases and trial registries up to February 2025, identifying 13 eligible trials involving 550 participants who receive the compound as a standalone intervention at doses from 50 to 900 mg per day over periods from a single dose to eight weeks. Outcomes include actigraphy, electroencephalography and participant-reported instruments covering sleep latency, maintenance, efficiency and satisfaction. The compound is rapidly absorbed after oral intake, with plasma levels peaking approximately 45 to 50 minutes after consumption.
Performance Evaluation: Beneficial effects are reported in 9 of 13 trials, including 9 of 11 using at least 200 mg per day. Actigraphic sleep efficiency improves by 2.8% with reduced wake after sleep onset of 7.2 min in one trial and by approximately 4% in boys with attention deficit hyperactivity disorder, while insomnia scores improve significantly compared with placebo in cancer patients. Doses of 200 to 450 mg per day appear safe and effective for supporting sleep quality.

L-Theanine as a Nutraceutical Intervention for Stress-Related Symptoms and Cognitive Function in Healthy Adults

Hidese, Shinsuke, et al. Nutrients 11.10 (2019): 2362.

L-Theanine acts as a psychoactive amino acid supplement that improves stress-related symptoms and cognitive performance in healthy adults, modulating glutamatergic neurotransmission through partial agonism at N-methyl-D-aspartate receptors.
Experimental Protocol: Thirty adults without psychiatric illness receive 200 mg of the compound or placebo tablets nightly for four weeks in a randomized, double-blind, crossover trial separated by a two-week washout based on a plasma half-life of about 65 min. Stress, anxiety, sleep and cognitive outcomes are assessed with validated questionnaires and neuropsychological batteries before and after each period, with all assessments completed in the morning between 10:00 and 12:00. Serum concentrations are measured chromatographically to confirm compliance.
Performance Evaluation: Self-rating depression scores, trait anxiety and sleep quality indices decrease significantly after treatment with P values of 0.019, 0.006 and 0.013, while placebo shows no change. Verbal fluency and executive function improve with P values of 0.001 and 0.031. Among participants with lower baseline function, verbal and letter fluency gains remain significant at P equal to 0.002. Serum theanine concentrations rise significantly with P equal to 0.002, confirming adherence, and no adverse events are reported.