Both versions of Zipslim provide the same Metabolic Reboot benefits, so it is simply a matter of personal preference. Most people like the extra energy they get from the 100mg of natural green tea caffeine in the Charged version. If you are sensitive to caffeine, or if you’re taking ZipSlim late in the day or before dinner, you may want to choose the Caffeine-Free version. It’s always wise to have some of each on hand!