Theanine
Overview
L-Theanine is an amino acid found naturally in tea leaves (Camellia sinensis). Studies suggest it may increase alpha brain wave activity associated with relaxed alertness. Commonly combined with caffeine. Typical doses are 100–400 mg/day. Safety profile is favorable with no established upper limit. A 2025 review notes that while safety evidence is good, clinical trial support for many brain health claims remains limited.
Dosage
200 mg · Evening · Can take on empty stomach
Key Interactions
15 verified interactions found
EGCG and caffeine diminish the anti-stress effects of theanine.
EGCG kann die beruhigende Wirkung von Theanin abschwächen. Bei gezielter Theanin-Supplementierung zur Stressreduktion mindestens 2h Abstand zu Grüntee-Extrakt einhalten.
View details →Theanine stimulates the release of glycine, enhancing the calming and anti-inflammatory effects of this amino acid.
Theanin kann die Glycin-Freisetzung im Nervensystem fördern; beide Aminosäuren wirken im inhibitorischen Neurotransmittersystem. Eine gleichzeitige Einnahme gilt als sicher.
View details →Spraying glycine betaine on young tea plants regulates leaf development, increases beneficial compounds like theanine and caffeine, and reduces chlorophyll, suggesting altered leaf metabolism.
Die Wechselwirkung zwischen Betain und Theanin ist aus Pflanzenstudien beschrieben; eine direkte Relevanz für Humansupplemente ist nicht belegt. Eine gleichzeitige Einnahme gilt als unbedenklich.
View details →Theanine promotes calm focus via alpha waves; B12 supports neurotransmitter synthesis and energy. Together they support cognitive performance without overstimulation.
Combine for balanced cognitive support.
View details →Theanine modulates glutamate for calm; DHA supports serotonin receptor function. Both contribute to balanced mood and cognition.
Combine for cognitive and mood support.
View details →What Experts Say
“100 to 400 milligrams of theanine taken, again, alone or in combination with the other supplements mentioned in the stack many people find allows them to get really drowsy and fall asleep, sleep really deeply, and they feel much more refreshed the next day and they don't have a grogginess to them”
Huberman recommends 100–400 mg L-theanine as part of his sleep stack, noting it promotes drowsiness and deep sleep without morning grogginess. It is taken alone or combined with magnesium threonate and apigenin 30–60 minutes before sleep.
Scientific Sources
- Influence of continued ingestion of matcha on emotional behaviors after social s (2019)
- Anti-stress effects of drinking green tea with lowered caffeine and enriched the (2016)
- Theanine Improves High-Dose Epigallocatechin-3-Gallate-Induced Lifespan Reductio (2021)
- Theanine enhanced both the toxicity of strychnine and anticonvulsion of pentobar (2016)
- Improving Albino Tea Quality by Foliar Application of Glycinebetaine as a Green (2021)
- Theanine + Vitamin B12 — no direct combination study found
- Theanine + DHA omega-3 combination study (PMID:41269033)
- NIH Dietary Supplement Label Database (DSLD)
- PubChem Compound 439378
Frequently Asked Questions
What is Theanine used for?
L-Theanine is an amino acid found naturally in tea leaves (Camellia sinensis).
What is the recommended dosage for Theanine?
200 mg. Evening. Can take on empty stomach.
Does Theanine interact with other supplements?
Theanine has 15 verified interactions. Top: Epigallocatechin Gallate, Glycine.
When is the best time to take Theanine?
Evening. Can take on empty stomach.
Is Theanine safe to combine with other supplements?
Always check interactions before combining supplements. Use VitalStack to verify your full stack for free.
Check how Theanine fits your full stack
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Check Your Stack →Not medical advice. VitalStack is not a medical device. For personalized health recommendations, consult a healthcare provider.