How guarana works in energy bars – and how much caffeine is in a gfBar
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Guarana grows in the Amazon as a vine that climbs up trees towards the light. When the fruit ripens, its red skin splits open and a black seed in a white casing peeks out. It looks just like an eye. The Sateré-Mawé people of the Amazon have a legend about it, and they have been growing guarana for centuries.
What matters to us is what’s inside the seed: caffeine – more of it, in fact, than in coffee beans.
Caffeine is caffeine
The caffeine molecule in guarana is exactly the same as the one in coffee or tea. Your body can’t tell where it came from.
It works simply. During the day a substance called adenosine builds up in the brain, and the more of it there is, the more tired we feel. Caffeine occupies the spots where adenosine would dock, and tiredness goes quiet for a while. It doesn’t create energy out of nothing; it just postpones the “I’ve had enough” signal.
You may have heard that guarana releases its caffeine more slowly than coffee. The usual explanation is that it’s bound to tannins in the seed. There are no convincing studies to back that up yet, so we won’t claim it.
What we can say is that in a gfBar, caffeine doesn’t arrive on an empty stomach like a morning espresso. It comes with food: fibre from blueberries, dates and chicory syrup, and fats from Brazil nuts.
How much caffeine is in a gfBar
We use a standardised guarana extract, so we know exactly how much caffeine each bar contains. One gfBar ORIGINAL bar has 40 mg, a whole box 80 mg.
For comparison, according to the European Food Safety Authority (EFSA):
| Drink or food | Caffeine |
|---|---|
| espresso (60 ml) | 80 mg |
| filter coffee (200 ml) | 90 mg |
| black tea (220 ml) | 50 mg |
| energy drink (250 ml) | 80 mg |
| cola (355 ml) | 40 mg |
| gfBar ORIGINAL, 1 bar | 40 mg |
| gfBar ORIGINAL, box (2 bars) | 80 mg |
How much is fine
EFSA considers up to 200 mg of caffeine in one go and up to 400 mg over a whole day safe for healthy adults. Pregnant and breastfeeding women should stay below 200 mg a day.
That’s why gfBar ORIGINAL is not recommended for children or for pregnant or breastfeeding women. If you’d like an energy bar without guarana, go for gfBar COCOA. We don’t add caffeine to it; only the small amount that cocoa naturally contains, just like any dark chocolate.
When to have it
Caffeine starts to work after roughly half an hour to 45 minutes. Half of it is still in your system about five hours later, give or take depending on the person. So morning, mid-morning or after lunch – yes. In the evening, better not, if you want to sleep well.
Before exercise, have a bar about half an hour beforehand.