Summary
L-Theanine has reached Preclinical as its most advanced recorded development stage across any indication, and the database holds no approval for Anxiety Disorders. ClinicalTrials.gov lists 7 registered trials linking L-Theanine to Anxiety Disorders: 2 are currently recruiting; 1 is active or not yet recruiting; 4 have completed. The most advanced is Phase 2 (NCT00291070). It plans or enrolled 100 participants. Registration activity spans 2005 to 2026. The literature layer holds 5 publications for this pair: 1 Cochrane review and 4 clinical trial publications. Publication years run from 2006 to 2023. Because at least one synthesis-level source exists (systematic review, meta-analysis or Cochrane review), this pair has been assessed beyond single studies, although the synthesis may concern a different indication.
The RepurpOS disease-intelligence file for Anxiety ranks 535 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: GAD: spontaneous remission in ~25-30% at 1 year without treatment; social anxiety: 36% remission at 12 years untreated; panic disorder: 50-65% spontaneous partial remission but relapse common; 40-60% remain symptomatic at 5 years.
Evidence table
| Evidence tier | C · Preliminary |
|---|---|
| Evidence score | 37.0 (trials 19.0, literature 13.0, tier 5, approved bonus 0.0) |
| Registered trials | 7 total: 2 recruiting, 1 active / not yet recruiting, 4 completed, 0 other |
| Linked publications | 5 (4 clinical trial publications, 1 Cochrane review) |
| Agent type | Supplement |
| Development stage (any indication) | Preclinical |
| Mechanism / class | Anxiety: a look at epidemiological factors and alternate treatments · Halma M, Covarrubias A, Selem E, Varon J · 2025 |
| Data sources | OSMF Chronic Disease Review |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT00291070 | Effects of L-Theanine in Boys With ADHD 2005 | completed | Phase 2 | 100 |
| NCT06505694 | A Clinical Trial to Assess the Impact of an Alcohol Alternative Herbal Tincture on Signs of Stress Anxiety and Sleep Quality. 2024 | completed | Not applicable | 80 |
| NCT05857956 | A Clinical Trial to Assess the Efficacy of a Plant-based Energy Shot on Focus and ADHD-like Symptoms 2023 | completed | Not applicable | 40 |
| NCT07665840 | Effects of L-Theanine and Hericium Erinaceus Gummies on Psychological, Cognitive, and Sleep Quality in University Students 2025 | completed | Not applicable | 67 |
| NCT07076537 | A Clinical Study on the Effects of a Dietary Supplement on Stress, Anxiety, Mood and Sleep in a Pediatric Population 2025 | not yet recruiting | Not applicable | 80 |
| NCT07319117 | Evaluation of the Impact of a Nutritional Formulation on Cognitive Performance Following Stress Exposure. 2025 | recruiting | Not applicable | 40 |
| NCT07135232 | The Effects of Resistance Training and a Plant-Based Supplement on Perimenopausal Symptoms and Muscle Health. 2026 | recruiting | Not applicable | 72 |
Published literature
- Clinical trial publication L-theanine combination therapy with fluvoxamine in moderate-to-severe obsessive-compulsive disorder: A placebo-controlled, double-blind, randomized trialNematizadeh M, Ghorbanzadeh H, Moghaddam HS et al. · Psychiatry and clinical neurosciences · 2023 · PMID 37169515
- Clinical trial publication Use of Nutritional Supplements Based on L-Theanine and Vitamin B6 in Children with Tourette Syndrome, with Anxiety Disorders: A Pilot StudyRizzo R, Prato A, Scerbo M et al. · Nutrients · 2022 · PMID 35215501
- Cochrane review Medicinal herbs for the treatment of anxiety: A systematic review and network meta-analysisZhang W, Yan Y, Wu Y et al. · Pharmacological research · 2022 · PMID 35378276
- Clinical trial publication L-theanine in the adjunctive treatment of generalized anxiety disorder: A double-blind, randomised, placebo-controlled trialSarris J, Byrne GJ, Cribb L et al. · Journal of psychiatric research · 2019 · PMID 30580081
- Clinical trial publication Relaxation and immunity enhancement effects of gamma-aminobutyric acid (GABA) administration in humansAbdou AM, Higashiguchi S, Horie K et al. · BioFactors (Oxford, England) · 2006 · PMID 16971751
Mechanism and notes
Recorded mechanism or class: Anxiety: a look at epidemiological factors and alternate treatments · Halma M, Covarrubias A, Selem E, Varon J · 2025.
OSMF's existing evidence tier for this pair is C (Preliminary), derived from the strength of the disease association recorded in OSMF Chronic Disease Review. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is L-Theanine approved for Anxiety Disorders?
L-Theanine has reached Preclinical as its most advanced recorded development stage across any indication, and the database holds no approval for Anxiety Disorders. Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is L-Theanine in clinical trials for Anxiety Disorders?
ClinicalTrials.gov lists 7 registered trials linking L-Theanine to Anxiety Disorders: 2 are currently recruiting; 1 is active or not yet recruiting; 4 have completed. The most advanced is Phase 2 (NCT00291070). It plans or enrolled 100 participants. Registration activity spans 2005 to 2026.
What does the evidence show for L-Theanine in Anxiety Disorders?
L-Theanine has both completed registered trials and synthesis-level publications linked to Anxiety Disorders. That is the strongest profile in this database, but the summaries here do not extract effect sizes, so read the linked reviews for direction and magnitude of benefit. OSMF's existing evidence tier for this pair is C (Preliminary), derived from the strength of the disease association recorded in OSMF Chronic Disease Review. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-05. Page built 2026-10-07.