Caffeine is the bitter substance that boosts the central nervous system to supply the energy that so many people rely on each day. While coffee may be the most familiar source of caffeine, guarana, an herb that comes from the Amazon rain forest, can provide the same energy-enhancing benefits. Guarana can be taken as a dietary supplement and has a history of use as a stimulant beverage.
New York University Langone Medical Center notes that both coffee and guarana contain alkaloids in the caffeine family. Caffeine has a number of uses, in addition to increasing energy. These include reducing pain, treating migraine headaches, enhancing sports performance and promoting modest weight loss. Similar to coffee, guarana is used primarily for its caffeine content. Many energy drinks and supplements use guarana as a source of caffeine. In addition to caffeine, guarana may contain other active ingredients that further its energy-promoting effects, though the evidence is still not clear.
In general, guarana has the same kind of effects as coffee on the body, and these are typically dose-dependent. According to NYU Langone Medical Center, a typical dose of guarana supplies somewhere in the neighborhood of 50 milligrams of caffeine. A cup of coffee contains approximately twice this amount. If you're consuming your guarana in energy drinks, however, you will likely experience energy from other ingredients, including other stimulants, vitamins, amino acids and sugar.
Columbia University's Go Ask Alice notes that because the U.S. Food and Drug Administration does not regulate dietary supplements, there may be some health risks associated with guarana. Reported side effects of guarana include heart palpitations, anxiety, flatulence and chest pain. Even cases of death have been reportedly linked to guarana use; however, there is no scientific evidence backing these claims. Go Ask Alice still recommends sticking to more regulated sources of caffeine, including coffee or tea, for safety reasons.
The side effects of coffee are well-documented and include dehydration, trouble sleeping, dependence, increased heart rate, jitteriness, nervousness and anxiety. MedlinePlus notes that most people can consume between 2 and 4 cups of coffee per day without experiencing side effects, though some people are more sensitive and may require a lower limit. Due to its extremely prevalent use, coffee can be considered a very safe and effective source of caffeine.