L‑Theanine
Green tea amino acid, γ-glutamyl-ethylamide, α-wave enhancer.
Pharmacology
Contents
WHAT IS L-THEANINE?
Detailed overview
L-Theanine (N-ethyl-L-glutamine, γ-glutamyl-ethylamide) is a free amino acid, the main non-protein amino acid component of Camellia sinensis (green tea) leaves. It crosses the blood-brain barrier (Tmax ~50 min) and enhances EEG α-wave activity in the relaxed-awake state (Nobre 2008, PMID 18296328). Combined with caffeine (the classical L-theanine:caffeine 2:1 or 200 mg:100 mg protocol) it synergistically improves attention (Foxe 2012, PMID 22849538) and reduces caffeine-induced vasoconstriction + anxiety. A single 200-400 mg dose can ease the stress response in healthy adults. Does NOT produce sedation or dependence – one of the safest anxiolytic nootropics. Also studied in pediatric ADHD syndrome (Lyon 2011 – improved sleep quality in boys). FDA GRAS.
Mechanism
GABA + α-wave + glutamate modulation
Onset
30-45 min oral
Legal status
OTC food + dietary supplement
Receptor profile
- Alpha brain wavesStrong
- GABA / glutamate balanceModerate
- Caffeine jittersModerate
- Glutamate (excitotoxicity)Weak
Safety
Side effects, stop signs, contraindications
Side effects · 5
- Headache, mainly at higher (>400 mg) doses
- Mild dizziness or lightheadedness in sensitive individuals
- Mild drowsiness or sedation at larger doses
- Mild GI upset or nausea on an empty stomach
- Slight lowering of blood pressure
Contraindications · 5
- Antihypertensive medication, due to additive blood-pressure-lowering effect
- Pre-existing low blood pressure, caution advised
- Sedatives or CNS depressants, additive sedation possible
- May blunt the effect of stimulants when taken together
- Pregnancy and breastfeeding, due to insufficient safety data
Related Nootropics
Same therapeutic category
FAQ
FAQ
L-Theanine is an amino acid found mainly in green tea, and it produces a calm, alert state without making you drowsy. In the brain it boosts what is called alpha-wave activity, which is linked to a relaxed but wakeful state of mind, so it is commonly used for relaxation and easing stress.
Telegram
Have a question about L‑Theanine?
Reach out to us on Telegram for a personalized stack. We'll be happy to help.
Personalized consultation
Want a detailed conversation tailored to your data?
Fill out the prep intake form (your goals, training and health data), and the advisor prepares from it to give genuinely personalized guidance.
Fill out the form~5–7 min · prep questionnaire · confidential · GDPR-compliant
Structure & chemistry
The information here is strictly for educational and scientific purposes. It does not replace medical advice or clinical consultation, and it does not encourage illegal substance or pharmaceutical use. Data is sourced. When in doubt, consult your doctor.