I am adding to my original review which follows. We went to Vietnam and Timeshifter again worked amazingly well. The time was almost exactly the opposite of our time. We were only gone 8 days. Timeshifter had me sleeping all night the first night in Vietnam and functioning great from the first full day there. Upon my return I slept well the first night and never experienced jet lag. I could not be more thrilled!! Remarkable! I travel monthly and am the worlds worse with jet lag for some reason. My husband bounces back and I spend a week waking up at 3 a.m. I am miserable and functioning poorly. My first trip using TimeShifter had me happily asleep all night from the day I left on my trip and again when I got home. I never had a sleepless or disjointed night sleep the beginning of my trip nor upon my return. I am thrilled!!!! Easy to follow and works!!! On a trip to Zimbabwe some years ago I was really out of sync and losing it. Finally turned to sleep meds which are awful too. So groggy. Wish this App had been available sooner. Next big test is in January. Vietnam is a day and 13 hours off my time I believe. Can’t wait to try my TimeShifter then. Customer service is AWESOME by the way. So worth the minimal cost for more enjoyable travel!!!! Thanks for this great travel aid!!!!!!