l-Theanine
CAM (enhances dopamine/serotonin, blocks glutamate, antioxidant, neuroprotective)
- Major Depression (augmentation), anxious depression2
- Hypnotic (safe in elderly, deepens sleep)3
- Non-specific Anxiety4
- OCD3
- Cognition in healthy adults3
- Schizophrenia anxiety and negative symptoms3
Features
Dosing
Depression and OCD: 200 mg qd
Sleep 200-400 qhs (or 200 mg bid) (also improves sleep in childhood ADHD)
Anxiety: Probably not effective, but may improve sleep, dose 200-600 mg qd (can divide bid, or can give 100-200mg q8hr prn)
Cognition 100-200 mg qd
Schizophrenia (negative symptoms and anxiety: 200mg bid
Management
An extract of green tea with neuroprotective effects. Augments antidepressants, possibly through glutamatergic mechanism. In anxiety has a mix of positive and negative studies.
It is the only medication that can be taken PRN for anxiety and is actually good for the brain!
TOLERABILITY: No problems
RISKS: None.
EMR Text
Depression
l-Theanine use based on a randomized controlled trial in depression, where it augmented antidepressants (Shamabadi A et al, J Affect Disord. 2023;333:38-43).
OCD
l-Theanine use based on a randomized controlled trial in OCD (Nematizadeh M et al, Psychiatry Clin Neurosci. 2023;77(9):478-485).
Schizophrenia
l-Theanine use based on multiple randomized controlled trials for negative symptoms of schizophrenia (Moshfeghinia R et al, BMC Psychiatry. 2024;24(1):886).
Insomnia
l-Theanine use based on randomized controlled trials in insomnia, where it improved sleep initiation, quality, and next-day functioning (Bulman A et al, Sleep Med Rev 2025;81:102076).
Cognition in healthy adults
l-Theanine use based on randomized controlled trials where it improved cognition and sleep in healthy adults under stress (Payne ER et al, Nutr Rev. 20252:nuaf054).
Anxiety
l-Theanine use based on small controlled trials in anxiety (Lopes Sakamoto F et al, Pharmacol Res. 2019;147:104395).