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Guarana is derived from the seeds of a South American tree. Because it’s high in caffeine, guarana has become a popular energy supplement.

Why do people take guarana?

Researchers once believed that the active ingredient of guarana was a chemical specific to the plant -- guaranine. But they later discovered that it was just caffeine. Guarana has among the highest concentrations of caffeine in any plant. It may contain up to 3.6% to 5.8% caffeine by weight. Coffee only has up to 2%.

Coffee and other caffeinated beverages seem to increase alertness when consumed throughout the day. Caffeine can improve mental performance and alertness in sleep-deprived people, and guarana would logically have the same effect.

Experts have not studied guarana extensively. So far, studies have not found that guarana is helpful for improving cognitive ability or mood. Some people use guarana to boost athletic or sexual performance. But there’s no evidence to back this up.

There’s some evidence that guarana – when used along with other supplements – may promote weight loss. It’s uncertain if the guarana specifically was responsible. Because caffeine is a stimulant that has been shown to improve mood and aid weight loss, guarana may very well also have these effects. As a weight loss supplement, caffeine may work best when combined with the polyphenol compounds in green tea. Combining guarana with polyphenols may have a similar effect. The safety of using guarana for weight loss is unknown.

Some believe that the effects of guarana are less intense and longer-lasting than caffeine. Studies have not established this.

How much guarana should you take?

There is no standard dose of guarana. For energy, some people use between 200 to 800 milligrams a day. Ask your doctor for advice.

Can you get guarana naturally from foods?

Besides the guarana seed itself, there are no natural food sources of guarana. It has become a common additive to some foods and drinks.

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