L-Theanine: Complete Guide
Amino acid from tea that promotes calm focus without drowsiness. Perfect caffeine pairing.
Quick Summary
Amino acid from tea that promotes calm focus without drowsiness. Perfect caffeine pairing. 100-200mg for calm focus. Best form: Suntheanine (patented).
What is L-Theanine?
L-theanine is an amino acid found almost exclusively in tea leaves (especially green tea). It crosses the blood-brain barrier and promotes a relaxed-but-alert state. Works within 30-60 minutes. No tolerance buildup.
Who Should Consider L-Theanine?
- Anyone who gets jittery from caffeine
- People with racing thoughts at bedtime
- Those wanting calm focus for work
- Anyone with mild anxiety
- Coffee drinkers who want smoothness without the crash
How It Works
L-theanine increases alpha brain waves (associated with relaxed alertness), boosts GABA, dopamine, and serotonin, and counteracts the jittery effects of caffeine. It calms without sedating. That's why tea feels different than coffee despite similar caffeine.
Forms Comparison
Different forms of L-Theanine have varying absorption rates and best uses. Here's how they compare:
| Form | Bioavailability | Best For |
|---|---|---|
| Suntheanine (patented) | 95% | Pure L-isomer. Most studied. Worth the slight premium. |
| Generic L-theanine | 90% | Usually fine. May contain some D-theanine (inactive). |
Our recommendation: Suntheanine (patented) for most people due to superior absorption and tolerability.
Benefits & Evidence
L-Theanine has 2 strongly-evidenced benefits and 2 moderately-evidenced benefits.
Calm focus
strong evidenceIncreases alpha waves within 40 minutes
Caffeine synergy
strong evidenceReduces jitters, improves focus more than caffeine alone
Sleep quality
moderate evidenceHelps quiet racing thoughts. Doesn't sedate.
Anxiety reduction
moderate evidenceModest but significant anxiolytic effect
Dosing & Timing
Recommended Doses
Timing
Side Effects & Interactions
Possible Side Effects
- Headache (rare). Rare
- No significant side effects. This is notably safe
Interactions to Know
- Enhances caffeine benefits while reducing negatives
- May enhance effects of sedatives
- Generally safe with everything
Frequently Asked Questions
2:1 (L-theanine:caffeine) is the classic stack. 200mg theanine + 100mg caffeine. Adjust based on your caffeine tolerance.
Related Topics
About this information: Our analysis of L-Theanine is based on peer-reviewed research from PubMed, ClinicalTrials.gov, and NIH databases. These statements have not been evaluated by the FDA. Supplements are not intended to diagnose, treat, cure, or prevent any disease.
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