NutriStack
Green Tea Extract and L-Theanine, a synergy.
L-theanine smooths the caffeine stimulation from green tea extract, improving sustained attention while reducing jitteriness and the post-caffeine crash.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Green Tea Extract and L-Theanine
- Pair type
- Synergy
- Evidence (highest tier)
- Strong
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Synergy · Strong evidence
Synergy
What is happening. L-theanine smooths the caffeine stimulation from green tea extract, improving sustained attention while reducing jitteriness and the post-caffeine crash.
Mechanism. Caffeine in green tea extract antagonizes adenosine receptors to raise arousal, while L-theanine increases alpha-wave activity and modulates glutamate and GABA tone, blunting caffeine-driven anxiety without abolishing the alertness benefit.
Recommendation. Pairing is favorable. A roughly 2:1 ratio of L-theanine to caffeine (for example 200mg L-theanine with 100mg caffeine equivalent) gives calm, focused alertness.
Sources (2)
- Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutritional Neuroscience. 2008
- Giesbrecht T, Rycroft JA, Rowson MJ, De Bruin EA. The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness. Nutritional Neuroscience. 2010
Stack Score
How this pair moves the number.
Effect on the composite score
If both Green Tea Extract and L-Theanine are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.