Guarana (Paullinia cupana)

Guarana is an Amazonian plant whose seeds are very high in caffeine. People take it for energy and focus, and it is added to energy drinks and some weight-management products. Practically speaking it is a caffeine source, so what it does is what caffeine does. The popular claim that its caffeine releases slowly for sustained energy has not been tested by the research cited here, and no study cited on this page measured weight, body fat or appetite.

Guarana seeds contain more caffeine by weight than coffee beans, so even small amounts provide a significant caffeine dose. Always count guarana's caffeine toward your daily total to avoid overdoing it.

Doses depend on the caffeine content, so follow the product label and keep total daily caffeine from all sources under about 400 mg for most healthy adults. Guarana is frequently combined with coffee, tea, pre-workouts or other caffeine sources in the same product, which makes it easy to go over without noticing. Pregnant women are commonly advised to limit caffeine to about 200 mg a day, so check with your doctor first.

Guarana is essentially a concentrated caffeine source, so the same cautions apply. Too much can cause anxiety, jitteriness, tremor, a racing or pounding heartbeat, insomnia and raised blood pressure. Be cautious if you take stimulant medication, or if you have a heart rhythm problem, an anxiety disorder, or high blood pressure that is not well controlled. Pregnant women are usually advised to limit total caffeine to about 200 mg a day. Because guarana is often stacked with other caffeine sources in the same product, check the label and add up your total.

Guarana is the seed of an Amazonian climbing plant — distinguished by extraordinarily high caffeine content (4-9% by weight, 4× more than coffee beans). It has been used by indigenous Amazonian peoples for centuries as a stimulant, and today it appears mainly in energy drinks and cognitive supplements.

The clinically studied dose is Products typically supply 75-200 mg of extract (roughly 30-100 mg caffeine) or 500-1,500 mg of whole seed powder. Count its caffeine toward your daily total. Always follow the product label and check with a healthcare provider for personal advice.

For most healthy adults, Guarana is well tolerated at studied doses. Reported effects can include: Caffeine-related: insomnia, anxiety, jitteriness, palpitations, tachycardia. GI distress. It may also interact with some medications. Guarana is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Possible interactions include: Standard caffeine interactions apply. Stimulant medication: effects add together on the heart and nervous system. Be cautious with ADHD medications, amphetamines and other stimulants, and with any other caffeine-containing product taken at the same time. If you take prescription medication, check with a pharmacist or doctor before using it.

NutraSmarts rates the evidence for Guarana as Limited (2 out of 5). It is backed by 2 clinical trials and 1 cited reference summarized on this page. A higher rating reflects more, larger, and better-designed human studies.