Caffeine 100 mg + L-theanine 200 mg
The best documented pairing for sustained attention, without the jitters of caffeine alone.
The short version
What it does Caffeine genuinely wakes you up, and theanine removes the jitters that come with it. The effect is immediate.
What it does not do It does not improve memory, and it corrects no cause of fatigue: it masks it. Taken too late, it costs an hour of sleep without you noticing.
What the studies say
Owen’s review on caffeine and cognitive performance establishes the effect on alertness, reaction time and sustained attention, with a curve that plateaus: above 3 mg/kg nothing improves further. Drake’s trial measured that caffeine taken 6 hours before bed still cuts sleep time by about an hour, without participants noticing.
Caffeine wakes you up but does not improve memory. And in a regular consumer, its most visible effect is mostly lifting the morning withdrawal.
It is the most effective product on this page for immediate alertness, and the one that costs the most in sleep if the timing is wrong.
How to take it
Relevant for a one-off dip or before a session. Useless if your fatigue is an iron, sleep or light deficit — there, caffeine masks the signal instead of fixing the cause.
1 to 3 mg per kilo of body weight. Last dose 8 to 10 hours before bed, not 4. Paired with theanine at a 2:1 ratio to smooth the jitters.
If you need a coffee to function in the morning, what you are measuring is dependence, not an effect. Try a week without: if the first three days are hard and then everything is fine, it was withdrawal.
What is inside
Anhydrous caffeine, synthetic or extracted, and L-theanine. Chemically identical to their natural equivalents.
The ratio matters: about 100 mg of caffeine to 200 mg of theanine. A capsule lets you dose precisely, which a coffee does not — the content of an espresso varies threefold.
Pre-workouts that stack caffeine, beta-alanine, yohimbine and ten extracts: you no longer know what is working or what is making you jittery. Caution in arrhythmia, anxiety, pregnancy.
Cautions
- Pregnancy
- Anxiety disorders
- Arrhythmia
- Uncontrolled high blood pressure
The three options
The ratio from the trials, to rebuild yourself
This product does not exist
The trials use twice as much theanine as caffeine. On Amazon.fr, every ready-made pairing comes in equal parts. Rebuild the ratio with two boxes: the option below, plus a theanine-only capsule.
For whom — Anyone who wants to reproduce exactly the pairing that was studied.
Nothing to buy here — the text above explains why.
Caffeine + theanine in capsules
100 mg of each, so equal parts
Both doses are stated, 240 capsules, 2,462 reviews. That is half the theanine used in the trials: add a theanine-only capsule on the days you want their ratio.
For whom — Everyday use before a session or a work block.
Theanine on its own, to add to your coffee
“L-Theanine (100 %)”: that is the whole list
Powder, not capsules, 100 g. The scoop holds 400 mg: take half of it for the 200 mg used in the trials, straight into the coffee. Only 22 reviews. The capsules are on the Theanine sheet, not here.
For whom — The cheapest option, and you keep your coffee.
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