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ingestible · for stress & anxiety

L-Theanine

Reviewed by the Nimbera editorial team · Last updated May 2026

Moderate evidence$10-25

How to use

Take 100-200mg L-theanine 30-60 minutes before a stressful event, or once daily for ongoing management. Also found in green tea at about 25mg per cup.

How it works

Amino acid that crosses the blood-brain barrier and increases alpha brain wave activity (associated with calm alertness) while reducing beta waves (associated with anxious rumination). Does not cause sedation.

Where to buy

Health stores and pharmacies. Often paired with caffeine (Smart Caffeine formulas) - the combination reduces caffeine jitteriness while maintaining focus.

Typical cost: $10-25

Safety notes

Generally well-tolerated. Can lower blood pressure - use caution if already taking blood pressure medications.

Drug & supplement interactions

  • Always tell your doctor or pharmacist about any supplements you take.
  • Interactions can occur with prescription medications, blood thinners, and immunosuppressants.
  • Herbal remedies can affect how the body absorbs or metabolises drugs.
  • Check drugs.com interactions checker before starting.

Clinical source

Journal of Clinical Psychiatry (RCT); Healthline

This information is compiled from primary clinical literature and is for informational purposes only. It is not a substitute for professional medical advice. Read our full disclaimer.