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Energy Supplements: Stimulants continued...

If you’re feeling groggy after lunch, what you really want is a stimulant. And for all the exotic herbs and amino acids sold as energy supplements, one of the most potent stimulants is also the most familiar: caffeine.

“Caffeine is a common ingredient in just about any product marketed for energy enhancement,” says Coates. And while an energy drink might have 25 other ingredients, the one you really feel is likely to be caffeine. “The amount of caffeine just swamps everything else,” Coates tells WebMD.

So how does caffeine work? “Caffeine and similar compounds do step up the metabolism temporarily,” says Roger Clemens, PhD, spokesman for the Institute of Food Technologists.  “That can make people feel better.”

Shao says that there’s pretty good evidence that caffeine can temporarily improve mental focus and, in athletes, help stave off exhaustion.

Although some products are seen as natural alternatives to caffeine, many actually contain caffeine itself or similar chemical substances that have similar effects. These include kola nut, yerba mate, and guarana. Green tea also provides a dose of caffeine and a related compound, theophylline, as well as the antioxidant epigallocatechin gallate (EGCG). It is possible that, because of these specific compounds, green tea may have unique effects on mental and physical energy.

Asian ginseng is not a caffeine derivative, but it may also serve as a mild stimulant. Will it help boost energy? There’s a lot of historical use of the different species of ginseng as tonics, says Coates. And a fair amount of scientific evidence exists for the three main “ginseng” species and their effects on psychological and physical health. For example, the effects of Siberian ginseng (eleutherococcus senticosus, often just called eleuthero) were studied in the Russian cosmonauts. The results indicated that there may be some benefit to stamina and “physical” energy. Capsaicin -- the ingredient that makes chili peppers hot -- is also sometimes used for its purported stimulant properties, but more for a metabolic boost than for obvious improvements in physical or mental energy.

Bitter orange, an extract from the rind of a different citrus species than that used for classic orange juice, is another energy supplement unrelated to caffeine. Though it hasn’t been studied much, some experts are concerned about potential risks. Its active ingredient -- synephrine -- is chemically similar to ephedrine, the active ingredient in ephedra, which was pulled off the market in 2004 because of its life-threatening health risks. Some preliminary reports have documentation concerning heart and vascular effects with the use of bitter orange. Coates says that bitter orange may prove a less harmful successor to ephedra, but more research needs to be done.

Bottom line: Will these supplements boost energy? Yes. Stimulants like these will probably rev up your metabolism temporarily and give you a lift. Are their effects superior to -- or even different from -- what you’d derive from a cup of coffee? Probably not.

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