What do the states mean?+
- Solid: well studied, and it works.
- Half-there: the science is still forming.
- A ghost: almost no real studies.
- Hollow: well studied, and it does not work.
- A cord: the pair itself has been tested together.
- Air: nobody has ever tested this pair.
The full scoring method: How we score
Can you take L-theanine and green tea extract together?
You don’t need to take them together.
As of August 2026, L-theanine and green tea extract have been tested together in 1 trial, in adults with mild cognitive impairment, and no clear added effect was found. Scored under the same rules as everything here.
11 studies · 1 tested the actual pair
What you’re seeing
- L-theanine renders solid: for sleep, it is well studied and it works.
- Green tea extract renders half-there: for weight and body fat, the science is still forming.
- The woven cord is the rare part: one trial gave both together, and no clear added effect was found.
You can tell before you read a word.
Magnesium + L-theanine are sold together in the same aisle. No trial has ever tested the pair. When that is true, we draw nothing between them. The nothing is the review.
The pair trial
- 2011Randomized trial · 91 people · adults with mild cognitive impairment · no clear effectsource
The other 10 studies on file tested each one alone. See all 11 studies
Fair questions
Is it safe to take L-theanine and green tea extract together?+
The studies on this page gave both together and reported no harm from the combination. That is not the same as a safety trial, and it says nothing about your dose or your medication.
How many studies is this based on?+
1 that gave the pair together. The papers are listed above with links to the source.
Deeper
What each one is on its own+
L-theanine
- Sleepsolid
- Memory and focushalf-there
- Moodhalf-there
- Stress and anxietyhalf-there
Green tea extract
- Weight and body fathalf-there
- Cancer preventionhollow
- Cholesterola ghost
- Inflammationhalf-there
- Memory and focushalf-there
Pairs that have been tested+
- L-theanine has been tested with L-arginine, chamomile.
- Green tea extract has been tested with turmeric, omega-3, iron.
These are the combinations someone has actually run a study on. Every other pairing here is air.