In recent years, caffeine has been popping up in all kinds of sports fuels, from gels to chews. And the latest delivery method promises an even faster jolt: chewing gum. Run Gum, created by two-time Olympian Nick Symmonds, contains 50mg of caffeine per piece, along with taurine (an amino acid found in meat and fish that supports brain development) and B vitamins. That gives a two-piece serving about as much caffeine as a standard cup of joe. Jolt Energy Gum has 40mg caffeine per piece plus guarana (a South American seed with twice as much caffeine as coffee) and ginseng, and Military Energy Gum packs 100mg caffeine per piece.

Why gum? “It [absorbs] faster than coffee or gels,” says Asker Jeukendrup, Ph.D., a professor of exercise metabolism at Loughborough University in the U.K. and a leading researcher on caffeine and exercise performance. The caffeine is absorbed quickly into the bloodstream through the lining of your cheeks. Plus, absorption through the skin has the potential to increase its bioavailability, giving you more vigor from fewer milligrams. Also, chewing any kind of gum has been shown to increase alertness, lower stress, and improve performance.

So far, the data look promising. One recent study from New Zealand found that caffeinated gum gave cyclists a stronger final push, increasing their power output during the final 10km of a 30km workout by nearly 4%. Still, there’s more research to be done to figure out the ideal timing and dosage. A 2010 study, in which athletes popped a piece five minutes before performing intervals, saw a 6% performance improvement, while the New Zealand study found that it took about 20 minutes for caffeine to kick in. Though the caffeine will stimulate, research suggests a tolerance to caffeine can occur in as few as four days if taken daily.

To find your ideal kick, Jeukendrup recommends starting with lower doses and experimenting. “Caffeine works with as little as 3 milligrams per kilogram,” he says.

But a stick of gum may not work for everyone. The New Zealand researchers noted that while caffeinated gum did improve cycling performance, only 13 subjects experienced the boost. Meanwhile, five had a negative reaction and two were nonresponsive. Researchers suggest the variability may be caused by differences in how people metabolize caffeine—akin to how one person can cap off dinner with a cappuccino and sleep like a baby, while another gets the jitters.

Want to try the trend yourself, but aren't into chewing gum? Here are four other workout-ready ways to get caffeinated.