Prime is very versataille but does have the tendancy towards recomp. If you want to lose weight while on it you could probably do it by running maintenance calories. Prime seems to dispose of extra calories somehow, maybe it's just the increased intensity of the workouts. The point is you can de anything you want with it, just depends on diet. The biggest reason a lot of people don't gain on it is they simply don't eat enough. If you bulk on it eat the extra calories, I mean above and beyond what you would normally, the gains tend to be very high quality.