L-Theanine
Also known as: Theanine, Suntheanine, N-Ethyl-L-glutamine
Category
amino acid
FDA Status
gras
Safety
low
Forms
3 types
What is L-Theanine?
L-Theanine is an amino acid found naturally in tea leaves that promotes relaxation without sedation. It's renowned for its synergy with caffeine, providing calm focus.
thumb_upBenefits
- checkRelaxation without drowsiness
- checkEnhanced focus when paired with caffeine
- checkReduced anxiety
- checkImproved sleep quality
How Does L-Theanine Work?
Increases alpha brain wave activity (8-12 Hz), modulates glutamate/GABA neurotransmission, crosses blood-brain barrier efficiently.
scaleDosage Guidelines
Recommended
200mg
Minimum
100mg
Maximum
400mg per dose
Timing: Any time; 30 min before stressful events
With food: Can be taken on empty stomach
Note: Synergistic with caffeine (1:2 ratio caffeine:theanine recommended).
Side Effects & Safety
warningPotential Side Effects
- • Generally well-tolerated
- • Mild headache at very high doses
do_not_disturbContraindications
- • Caution with antihypertensive medications
- • Hypotension risk
Drug Interactions
L-Theanine may interact with certain medications.
- arrow_rightNo major interactions known
scienceScientific Evidence
Reduces anxiety without sedation
strong evidenceMultiple studies show L-theanine reduces stress markers and promotes relaxation.
Based on 200 studies
shopping_bagWhere to Buy L-Theanine
No product recommendations available at this time.
swap_horizLegal Alternative To
L-Theanine is commonly used as a legal alternative to these restricted substances:
Learn More
Research articles and educational resources
Overview
Theanine
Theanine, also known as L-γ-glutamylethylamide, N5-ethyl-L-glutamine, or γ-glutamylethylamide, is a bioactive, non-proteinogenic amino acid similar to the proteinogenic amino acids glutamic acid and L-glutamine. It is produced by certain plants such as the tea plant, and by some fungi. Theanine was discovered in 1949 as a constituent of green tea and was isolated in 1950 from gyokuro tea leaves. Theanine constitutes about 1–2% of the dry weight of green tea leaves.
Scientific Research
From PubMed • 3 peer-reviewed studies
L-Theanine and Immunity: A Review.
L-theanine (N-ethyl-γ-glutamine) is the main amino acid in tea leaves. It not only contributes to tea flavor but also possesses several health benefits. Compared with its sedative and calming activities, the immunomodulatory effects of L-theanine have received less attention. Clinical and epidemiological studies have shown that L-theanine reduces immunosuppression caused by strenuous exercise and prevents colds and influenza by improving immunity. Numerous cell and animal studies have proven that theanine plays an immunoregulatory role in inflammation, nerve damage, the intestinal tract, and tumors by regulating γδT lymphocyte function, glutathione (GSH) synthesis, and the secretion of cytokines and neurotransmitters. In addition, theanine can be used as an immunomodulator in animal production. This article reviews the research progress of L-theanine on immunoregulation and related mechanisms, as well as its application in poultry and animal husbandry. It is hoped that this work will be beneficial to future related research.
L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications.
Tea (Camellia sinensis L.) is a very popular health drink and has attracted increasing attention in recent years due to its various bioactive substances. Among them, L-theanine, a unique free amino acid, is one of the most important substances in tea and endows tea with a special flavor. Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects. Due to the unique characteristics and beneficial functions, L-theanine has potential applications in the development of functional foods. This review summarized the influencing factors of L-theanine content in teas, the main health benefits and related molecular mechanisms of L-theanine, and its applications in food, understanding of which can provide updated information for the further research of L-theanine.
The effects of L-theanine supplementation on the outcomes of patients with mental disorders: a systematic review.
When utilized as an adjunct with antidepressants, antipsychotics, and other psychopharmacological drugs, certain amino acids, such as L-Theanine (LT), have shown potential effectiveness in enhancing the symptomatic outcomes of patients with mental disorders. Despite this, there is a lack of previous systematic reviews examining these associations. Therefore, we conducted a systematic review of randomized controlled trials examining these relationships.