L-Theanine

Sleep & relaxation

Function & benefits

A natural amino acid found in green tea leaves; it crosses the blood–brain barrier and promotes alpha brain waves, giving a state of calm alertness and relaxation without drowsiness.

Dosage & how to use

Recommended dose	100–200 mg
Best time to take	In the morning (often 1:2 with caffeine for calm focus) or in the evening to support relaxation
Frequency	1–2 times daily

Important warnings

Its clinical safety is very high up to 400 mg per day

Pregnant and breastfeeding women are advised to avoid concentrated supplements because clinical safety data are limited

Drug interactions

It may enhance the effect of blood pressure medicines and sedatives that act on the central nervous system.

Scientific references

Nobre AC et al. Asia Pac J Clin Nutr 2008 — PMID: 18296328

View in the supplements guide

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📚 Published sources and research: European Food Safety Authority (EFSA) • National Institutes of Health (NIH - ODS) • PubMed / Cochrane databases

Content last updated: 17 October 2026 · Based on published sources and research (EFSA / NIH / PubMed)

⚖️ Medical disclaimer: The information and data provided here are for health education and nutritional guidance only. They are not a medical diagnosis and never replace a direct consultation with your doctor or pharmacist. Always consult your doctor before starting any supplement, especially during pregnancy or breastfeeding or when taking long-term medication.