I read a lot of great reviews about this app but was a little skeptical. But I decided to try it anyway. The first trip was free and I had the perfect testing ground- 10 days in remote Africa (8 hour time difference)- with almost 100hours of travel to make it round trip. I entered my flight info and followed all of the travel, caffeine, light, and sleep suggestions starting three days before departure. Guys! It was amazing! Worked beautifully. I would have totally slept at the wrong times. But, following the plan, I am happy to report i experienced NO jet lag while two of my travel companions struggled. The fourth in our party of 4 also used the app (at my suggestion) and was jet lag free. BOOM! Definitely recommend! Thanks for this great travel tool!