Guarana Side Effects

Guarana contains between 3.6% to 5.8% caffeine, well over two times the amount present in coffee beans. As a result, the effects of guarana are usually attributed to its caffeine content. However, according to this 2007 study, Haskell CF, Kennedy DO, Wesnes KA, Milne AL, Scholey AB. A double-blind, placebo-controlled, multi-dose evaluation of the acute behavioral effects of guarana in humans. J Psychopharmacol. 2007 Jan;21(1):65-70., a 75 mg guaraná dosage provides cognitive improvements that cannot be attributed to caffeine alone. So the scientic jury is still out as it were.

The guarana content of energy drinks varies extensively, ranging from 1.4 to 400 mg of guarana per 240mL. While guarana’s side effects are related to its high caffeine content, it is usually accepted as a safe food ingredient at the typical dose of 1 gram per day. Nevertheless, guarana use could cause extreme anxiousness and lack of sleep in people sensitive to caffeine, and if consumed in doses in excess of 3 g/day, caffeine toxicity may result. Guarana should not be used by those who are pregnant or even lactating, have panic attacks, hyperthyroidism, glaucoma, cardiovascular diseases or bleeding disorders and should not be taken when formulated with ephedrine in diet aids as well as performance enhancing drugs. Life-threatening unusual heartbeats have been recorded to occur.

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