L-theanine: what it is and where it is found
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L-theanine is an amino acid found naturally in tea leaves. A cup of black tea contains roughly 25 mg, and it is also sold as an ingredient in food supplements. No health claim for L-theanine is authorised in the EU, so this guide covers what it is, where it is found and what to look for on a label.
In short
• L-theanine is an amino acid from the tea plant (Camellia sinensis).
• A 314 ml cup of black tea made with a 2 g tea bag contained about 25 mg in one study.
• Coffee contains no L-theanine.
• EFSA assessed proposed health claims for L-theanine in 2011; none are authorised in the EU.
Contents
- What is L-theanine?
- Where is L-theanine found?
- L-theanine and health claims in the EU
- L-theanine on a supplement label
- FAQ
What is L-theanine?
L-theanine is an amino acid that occurs naturally in the leaves of the tea plant. It is not one of the amino acids your body uses to build proteins. As an ingredient, it is usually a white powder made by fermentation or extracted from tea.
Where is L-theanine found?
| Source | L-theanine |
|---|---|
| Black tea, 314 ml cup (2 g tea bag) | about 25 mg (one study) |
| Green tea and matcha | yes, amount varies |
| Coffee | none |
| Optimal Native Morning Energy / Daily Flow | 50 mg per pouch |
| Optimal Native Evening Relax | 100 mg per pouch |
Tea figure: van der Pijl et al., Journal of Functional Foods, 2010. Longer brewing increases both the caffeine and the L-theanine in tea. More: How much caffeine is in tea? · Caffeine in matcha
L-theanine and health claims in the EU
In the EU, a health claim may only be made for a food or supplement if it has been authorised. EFSA assessed proposed claims for L-theanine from tea in 2011 (EFSA, 2011), and no health claim for L-theanine is authorised. Products may state that they contain L-theanine and how much, but not that it has a particular effect.
L-theanine on a supplement label
- Amount per serving: listed in mg.
- Other ingredients: it is often combined with caffeine. Check the caffeine per serving too.
- Warnings: products with added caffeine must say "Contains caffeine. Not recommended for children or pregnant women".
Optimal Native pouches contain L-theanine together with caffeine (Morning Energy 200 mg, Daily Flow 75 mg) or without caffeine (Evening Relax). Morning Energy and Daily Flow also contain vitamins B6 and B12, which contribute to normal energy-yielding metabolism and the reduction of tiredness and fatigue. More: Caffeine pouches explained
FAQ
Is L-theanine in coffee?
No. L-theanine comes from the tea plant.
How much L-theanine is in a cup of tea?
About 25 mg in a 314 ml cup of black tea in one study; it varies with the tea and brewing.
Is L-theanine a stimulant?
No. It is an amino acid. It contains no caffeine.