Ingredient
L-Theanine
Research dose
100–200 mg
Evidence: Weak Taken before training: what counts is the amount in the serving you take.
Studied for focus and attention, mostly together with caffeine (about 100 mg), or 200 mg on its own; the two small exercise trials disagree.
Sources
Owen GN, Parnell H, De Bruin EA, Rycroft JA. The combined effects of L-theanine and caffeine on cognitive performance and mood. Nutr Neurosci. 2008;11(4):193-198.
Supports the research dose. Where: Abstract: "50 mg caffeine, with and without 100 mg L-theanine". Read the source, checked 7 Oct 2026.
Payne ER, Aceves-Martins M, Dubost J, Greyling A, de Roos B. Effects of Tea (Camellia sinensis) or its Bioactive Compounds l-Theanine or l-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of RCTs. Nutr Rev. 2025;83:1873-1891.
Supports the research dose. Where: Results: theanine-only interventions, "the median theanine dose was 200 mg". Read the source, checked 7 Oct 2026.
L-theanine supplements we've checked
13 L-theanine supplements, each judged on how much a day its label's own directions give. See them all, ranked.
In the pre-workouts we've checked
| Product | Per scoop | Verdict |
|---|---|---|
| 1st Phorm Project-1 | 200 mg | Effective dose |
| NutraBio PRE | 300 mg | Effective dose |
| Alpha Lion SuperHuman Supreme | 150 mg | Effective dose |
| Legion Pulse | 175 mg | Effective dose |
| Transparent Labs BULK Black | 200 mg | Effective dose |
| PEScience Prolific | 100 mg | Effective dose |
| RYSE Loaded Pre | 50 mg | Below research dose |
| Transparent Labs BULK | 200 mg | Effective dose |
| Thorne Advanced Pre-Workout | 100 mg | Effective dose |
| Ladder Pre-Workout | 200 mg | Effective dose |
| Alani Nu Pre-Workout | 200 mg | Effective dose |
| GAT Sport Nitraflex | In a blend | Hidden in a blend |
| Jacked Factory Wick Mode | 50 mg | Below research dose |
| ProSupps Mr. Hyde Xtreme | 50 mg | Below research dose |
| EVLution Nutrition ENGN | 50 mg | Below research dose |
| Transparent Labs LEAN | 180 mg | Effective dose |
| Bloom Nutrition High Energy Pre-Workout | In a blend | Hidden in a blend |
| Jacked Factory Nitrosurge | 90 mg | Below research dose |
| Jacked Factory Nitrosurge Shred | 90 mg | Below research dose |
| Jocko Fuel Go Pre-Workout | 95 mg | Below research dose |
| Nutrex Hemo-Rage | In a blend | Hidden in a blend |
| Performance Lab Pre Lab Pro | 160 mg | Effective dose |
| ProSupps Mr. Hyde | 26 mg | Below research dose |
| RAW Nutrition CBUM Thavage | 75 mg | Below research dose |