I've tried both and mid day as well. I prefer mornings because after your workout, you feel great and you tend to be more conscious about your decisions in eating healthy throughout the day. At night time (which i do now) is the only time i have to workout (after I put my baby to sleep) I get a little hyper, but after my shower it relaxes me and I get to sleep better. When I was younger (lived closer to my job) i worked out around 3pm., and it was good too, because I got enough energy to do the rest of my errands the rest of the day. Morning workouts is better, but for me Night time is great for now..