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There's no shortage of energy drinks claiming to keep you focused and clear your mind.  But what's really in these drinks?

The answer, according to several energy drink manufacturers, is citicoline, a stimulant added to many popular drinks, including 5-Hour Energy Shots.

The Washington Post reported Tuesday that citocoline is now being added to more energy drinks and supplements. But do the facts support the claims?

One of the latest drinks to come to market, Nawgan (pronounced "noggin"), promises that one can a day can "sharpen your  mind."  The site even urges users to track their mental performance using an online memory and focus test.

"It helps with alertness and concentration by providing nutrients the brain needs for alertness," said Jim von der Hoyt, CEO of Nawgen, which is based in St. Louis, Mo.

According to a study on the   company's website, citicoline can help improve focus and mental energy, and potentially manage symptoms of attention deficit disorder.

Yet many experts caution consumers to beware of beverages making any health claims. In fact, studies regarding citicoline, better known by its brand name Cognizin, conflict with overwhelming evidence suggesting that the supplement is no better than a placebo.

And if consumers are buying these products to drink up the health claims on the bottle,  experts say the desired quick fix may not be there. "If you need energy, you might need more sleep, not a drink," said Keith Ayoob, associate clinical professor of pediatrics at the Albert Einstein College of Medicine in New York City.

Ayoob suggests that more research is needed before citocoline should be considered the go-to solution for focus or energy.  "One study is never enough to build a drink on or change your entire diet," he said.

The makers of Nawgen say the drink is not meant to be a cure all. "We're not the least bit claiming this is a medication at all.  This is considered a functional beverage," said von der Hoyt.

Americans spent about $9 billion last year on energy drinks, according to the Council for Responsible Nutrition.   Citocoline drink products account for only a portion of all energy drink sales.  In fact, in most energy drinks, it's more likely caffeine or sugar providing the energy jolt.

In the U.S., citicoline is also marketed in much lower doses as a dietary supplement, found in capsules, drinks and gel packs.

Von der Hoyt said he does not consider Nawgen to be among the category of energy drinks - rather, he says it's an "alertness beverage."

"It helps with alertness and concentration by providing nutrients the brain needs for alertness," said von der Hoyt.

Beverage manufacturers and supplement makers in the U.S. are not required to prove certain  health claims.  But the U.S. Food and Drug Administration does require companies to ensure their products are safe before going to market. And once on shelves, the agency can review any product for safety.

In some European countries, citocoline is approved as a prescription drug to help improve memory decline and increase brain function immediately after  stroke.

There's no evidence suggesting that taking citicoline is unsafe, according to Ayoob, who added that it's okay to drink if you  like the taste. But the body creates the citicoline naturally, he said, and a healthy diet is more important to support daily function than consuming an energy drink.

"If somebody's worried about brain function, what they don't need is a drink," said Ayoob. "They need to put efforts towards physical activity."