Caffeine & Theanine: PWO

We've covered caffeine before and have found it to be an effective (albeit controversial due to tolerance) PWO and PED. For years I've heard about the synergy of Theanine and Caffeine together as it relates to being a nootropic, generally in /r/nootropics as one of the most basic combinations of compounds. What I'd like to talk about here is its potential effects in a physical performance capacity.

The TL:DR is that there's no direct data that I could find on theanine + caffeine on strength or endurance. That said, it has two important effects that I would expect would be beneficial to the average PEDsR reader... focus / concentration and blood pressure.


While its effects may vary from person to person, improvements in various measurements of attention increased significantly.

Another study uses the Profile of Mood States (POMS) as a method of ranking mood in various ares. These are Tension-Anxiety (T-A), Depression-Dejection (D), Anger-Hostility (A-H), Vigor-Activity (V), Fatigue-Intertia (F), and Confusion-Bewilderment (C). Compared to placebo, Theanine & Caffeine had the following independent effects:

  • Tension-Anxiety (T-A): ~40% improvement from caffeine, and ~80% improvement from theanine
  • Depression-Dejection (D): ~10% improvement from caffeine, and ~80% improvement from theanine
  • Anger-Hostility (A-H): ~30% improvement from caffeine, and ~50% improvement from theanine
  • Vigor-Activity (V): Marginal improvement from caffeine and theanine
  • Fatigue-Intertia (F): Marginal improvement from caffeine, and ~80% improvement from theanine
  • Confusion-Bewilderment (C): ~10% improvement from caffeine, and ~80% improvement from theanine

Graph available here

Note: There are many studies replicating these results. In reading through them, you'll likely notice that the measurements made are difficult / impossible to quantify as a % increase. While the studies are usually a cross-over and leave little doubt as to the improvement of theanine + caffeine in this space, it's not something you can easily say X dose increased concentration by X%. POMS, as a subjective measuring tool, is about as accurate a measurement as we might expect in this area.

Blood Pressure

n=14. L-theanine significantly inhibited the blood-pressure increases in people who ordinarily had significant increases in blood-pressure when under stress. Caffeine tended to have a similar but smaller inhibition of the blood-pressure increases caused by the mental tasks.

Theanine lowered blood pressure by up to 20mg/Hg after cognitive stress, and in a recovery period lowered blood pressure by up to 10mg/Hg.

Tieing These Results Together

So far, we've established that Theanine + Caffeine has benefit to concentration and blood pressure - both likely to help improve performance and endurance. The missing leg of the proverbial stool is to understand if the theoretical improvements in performance translates into strength, endurance or physical composition... and to which we are somewhat blind on. While I wouldn't expect it to have the same direct benefits of, say, citrulline, it remains a theoretical.

The indirect evidence, however, would indicate that lowering stress before a workout is a good thing. In one study (n=20), experienced runners performed 2 x 3km runs, once after cognitive fatigue, and once non-fatigued. Completion times in a stressed state were on average about 13 seconds slower.

(Unfortunately I couldn't find any studies doing the same time of study as it relates to strength.)

In terms of supplementation, I am generally a minimalist. The theory being, the less being taken (or the lower the dose), the less chance there is for something to go wrong / lower potential side effects. For this reason, I could see adding in a simple PWO of caffeine + theanine fitting into my supplementation routine (perhaps adding creatine in, epicatechin etc.). It is theoretically going to be effective and cost efficient.