Stimulant
Guarana
A plant-based stimulant containing caffeine, used to enhance energy and alertness.
KÖGN Health grades Guarana as A (Strong evidence) and rates it 4.1 out of 5.
Last reviewed · June 2026
Primary effects
- Increased energy
- Improved focus
- Reduced fatigue
How it works
Provides a sustained release of caffeine, improving alertness and reducing fatigue.
Overview
Guarana contains caffeine along with other compounds that slow its release, leading to a more sustained energy boost compared to coffee. It is commonly used in energy and performance formulations. While effective for focus and alertness, it shares similar limitations to caffeine, including potential tolerance and overstimulation at higher doses.
The evidence
Guarana is an Amazonian plant whose seeds are a concentrated source of caffeine. Acute studies report small improvements in alertness, reaction time and secondary memory — interestingly at low doses, and not fully explained by caffeine alone — though a 2023 meta-analysis found only a small effect on response speed. In practice it is a caffeine-delivery botanical with a modest extra.
How to dose it
Acute studies span roughly 37.5–300 mg of guarana extract; the caffeine content varies widely between products, so check the label.
When to take it
Acute.
Safety & side effects
As with caffeine: jitteriness, raised heart rate and disturbed sleep at higher intakes.
Who should avoid it
Apply caffeine cautions — pregnancy, anxiety disorders, arrhythmias — avoid late in the day, and count it toward your total daily caffeine, as guarana products can be surprisingly potent.
References
Related ingredients
Graded entries that target the same cognitive goals.
Categories
Draft — the dose, safety and evidence notes on this entry were prepared from the published literature and are pending editorial and clinical review.
Educational information, not medical advice. The evidence grade is KÖGN’s editorial assessment of published research, not a health claim. Speak to a qualified clinician before changing what you take.