You suck on the lozenge for a seconds then put it between your cheek and gums until you feel like its not working anymore then suck on it again. The full size ones last about 45 mins the minis an hour. It comes in 2 or 4 mg. Dont confuse that with juice strength. Even when I was using 24 mg juice I was using 2 mg lozenges. Keeps me from crawling up walls.How does that work? Any cravings? How long does one last before you have to repeat?