"If losing weight was one of your New Years resolutions you might already be growing weary of counting calories and working out. Wouldnt it be great if you could slim down without so much effort Anyone looking for a shortcut to weight loss might be tempted to try one of many supplements that claim to burn fat and boost metabolism. These products often contain a notespeciallyexotic ingredient thats already a staple of the American lifestyle caffeine. The morning coffee drinkers at Dunkin Donuts notwithstanding caffeine has a strong reputation as a weightloss aid. The stimulant is one of the key ingredients of Zantrex the popular weightloss supplement from Zoller Laboratories based in Salt Lake City. The company claims each capsule contains up to  milligrams of caffeine and caffeinelike stimulants from green tea and yerba mate among other sources while a government database of supplements says each capsule of Zantrex contains more than  mg of caffeine. Thats slightly more than youd get from a typical double shot of espresso. Other ingredients include ginseng and damiana a Latin American herb traditionally used as an aphrodisiac. Users are instructed to take two capsules with a glass of water before a meal or anytime during the day when they need an energy boost. According to the label they shouldnt take more than six capsules in a day. Zantrex is available at many drugstores. You can expect to pay about  for a package of  capsules. Its What We Have Suspected All Along And Even Worse... LipoFuze a weightloss supplement from E Nutrition Research based in Orem Utah also packs a significant amount of caffeine. The label says that each capsule contains  mg of a green tea extract that is  caffeine. Other ingredients include vitamin D chromium and coenzyme Q. Users are instructed to take two capsules a day. A package of  a onemonths supply costs about . The claims The website for Zantrex says it provides both extreme energy and rapid weight loss   more weight loss than the leading ephedrabased diet pill to be exact. The site features a picture of reality TV star and official product endorser Nicole Snooki Polizzi of Jersey Shore pulling a bottle of the pills out of her purse. The website calls her a celebrity and yes the term is in quotation marks. Amy Heaton director of scientific affairs for Zoller says that caffeine and caffeinelike compounds have been proved to improve energy stamina concentration mood and metabolism. But she says they have not been shown to significantly increase weight loss. Heaton adds that its not just about weight loss. Its about fat loss and increased energy. To drive home the message she points to Snookis transformation from a selfprofessed meatball to a sexy and slim fireball. The website for LipoFuze says that the supplement increases the metabolic mechanism in your body. The site also says the green tea and caffeine will rev up your metabolism and increase energy focus and physical performance. The site features testimonials it says are from users who claim they have lost huge amounts of weight with the help of LipoFuze. One man says he dropped more than  pounds although its unclear how long that took. A woman says she lost  pounds in less than a year including  pounds in her first month. Attempts to reach E Nutrition Research for comment were not successful. The bottom line Caffeine shows up in a lot of weightloss products but it doesnt seem to be any sort of silver bullet against flab says C. Michael White a professor of pharmacy at the University of Connecticut in Storrs. White says that to his knowledge there are no welldesigned studies showing that caffeine works better than a placebo when it comes to weight loss. White notes that caffeine is a diuretic which means that people taking large doses might shed some weight through water loss but thats not the kind of slimming most users are looking for. As reported in a  issue of the International Journal of Obesity caffeine may in fact be able to increase a persons metabolic rate by  or . But according to White theres no clear evidence that this translates into actual weight loss. One possible explanation Any increase in metabolism might go handinhand with a boost in appetite he says. Caffeine does seem to enhance the weightloss powers of some other ingredients White says. For example green tea contains antioxidants that encourage cells to burn extra calories and caffeinated green tea seems to promote more weight loss than decaf versions. But even this combination yields very modest results. In clinical trials the weight loss is . to  pounds not  pounds White says. Gerald Endress the fitness director of the Duke Diet and Fitness Center at Duke University in Durham N.C. says patients often ask about caffeine as a weightloss aid. I tell them its definitely not going to be as helpful as  minutes of exercise. Endress says a little caffeine before a workout might help a person exercise harder and longer which could theoretically help them control their weight. But the real credit would go to the exercise not the caffeine. Endress also warns that too much caffeine  such as the high doses found in Zantrex  could cause jitteriness anxiety spikes in blood pressure and rapid heartbeats in some people."