Guarana

Paullinia cupana

Seeds & Grains. Latin American & Amazon and Modern nutrition.

Also called Guaraná, Brazilian cocoa

Spanish: Guaraná

Caffeine-heavy; heart and sleep risks

Guarana is the seed of an Amazon vine, high in caffeine, and it is used in energy drinks and supplements.

Did you know? Local legend says the first guarana plant grew from the eyes of a child, and the seed looks like a human eye.

What it may help, and how strong the proof is

Memory & focus. A randomized, double-blind study of 129 young adults found faster, more accurate thinking after one dose. It mixed guarana with vitamins, so guarana's own effect is hard to separate.
Early proof
Energy & tiredness. Sold for energy and fatigue. Trials of guarana alone are limited, so this rests mostly on caffeine.
Traditional proof
Weight. Weight loss claims come mostly from blends and caffeine. Guarana alone has no good weight-loss proof.
Traditional proof

Parts of the body

Brain & mind, Energy & metabolism

Traditional use

The Sateré-Mawé people of the Brazilian Amazon have used guarana seeds for centuries, grinding them into a paste or drink for energy and to fight tiredness.

How it is classified

Herbal actions: Stimulant, Brain tonic. Energy: neutral.

How people take it

Taken as powder or capsules, or drunk in energy drinks. Studies have used doses from about 75 mg to 1,000 mg a day, so there is no clear standard dose.

Powder, capsule and food.

Where to get it

Grows mainly in the Brazilian Amazon. Seeds are roasted, ground, and mixed into drinks, powders, and capsules. Labeled caffeine content is often wrong.

Be careful

Guarana is high in caffeine. Too much can cause a fast heartbeat, anxiety, insomnia, and stomach upset. Avoid it in pregnancy and breastfeeding, because caffeine has been linked to low birthweight and preterm birth.

Avoid if: pregnancy; breastfeeding; heart disease; anxiety disorders.

Mixing with other things

Use caution
Blood pressure medicine (lisinopril, amlodipine, losartan)
Caffeine from guarana can raise blood pressure, which matters with blood pressure medicines or high blood pressure.
Use caution
Sleep or anxiety medicine (Ambien, Xanax, Ativan)
Caffeine can cancel out the effect of sedatives and sleep medicines.
Use caution
Antibiotics (doxycycline, Cipro and similar)
Some antibiotics, such as ciprofloxacin, slow caffeine clearance and can make jitters worse.
Use caution
Alcohol (beer, wine, spirits)
Alcohol adds to the drowsiness.

Adds up with others that can make you drowsy: , , , , , , , , , , , , , and 14 more.

The honest take

Guarana is mostly a caffeine source, and its unique benefits are not proven. The main study mixed it with vitamins, so the seed's own effect is unclear. Labels are often wrong about caffeine, so use caution, especially with heart or sleep problems.