Our experience using it before Kiwi was that it definitely works. By the 2nd day we were using it, we could tell it was working and our internal clocks were being reset. We adapted very quickly by time of our arrival in Auckland. On the way home, I just couldn't see me wearing ugly yellow sunglasses to avoid light, so we didn't use Entrain and it took over a week for us to get back on schedule. We bought these cheap but ugly Uvex blue light blocking sunglasses (make you look like Bono from U2) and an inexpensive portable 10,000 lux light box by Circadian Optics from Amazon. Let me know if you have questions. Next time for Batik I plan to use it in both directions.