GuaranaIN THIS ARTICLE
How does Guarana work?Guarana contains caffeine. Caffeine works by stimulating the central nervous system (CNS), heart, and muscles. Guarana also contains theophylline and theobromine, which are chemicals similar to caffeine.Are there safety concerns?Guarana is safe for most adults. The caffeine in guarana can cause insomnia, nervousness and restlessness, stomach irritation, nausea, vomiting, increased heart rate and blood pressure, rapid breathing, tremors, delirium, diuresis, and other side effects. Large guarana doses might cause headache, anxiety, agitation, ringing in the ears, pain when urinating, stomach cramps, and irregular heartbeats. People who take guarana regularly may experience caffeine withdrawal symptoms if they reduce their usual amount.If you are pregnant or breast-feeding, guarana should be taken with caution due to the caffeine content. Small amounts are probably not harmful; however, consuming more than 200 mg/day has been linked to an increased risk of miscarriage and other negative effects. Avoid consuming large amounts of guarana if:
Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. Need help identifying pills and medications? ![]() Report Problems to the Food and Drug Administration You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088. |
Women's Health
Find out what women really need.
From WebMD
Featured Centers
Health Solutions From Our Sponsors
Featured Topics
Medical Dictionary
Pill Identifier on RxList
- quick, easy,
pill identification
Find a Local Pharmacy
- including 24 hour, pharmacies



