Hi Jennifer,
Sorry to take so long to reply...I'd been taking Glucophage XR for about six months now, and I've become used to the 500mg. I just recently switched to generic Metformin ER because it's now finally available in Canada and it's 30 bucks cheaper for a 3 month supply. Right now I'm actually wondering if I'm doing more harm than good by not taking 1000mg because my doc said after a while your body develops some sort of resistance or something, and you keep having to increase the dosage

So maybe I should consider taking two a day again, and see how my quality of life changes,

But I'll tell you, these past six months have been a horrific rollarcoaster of sicknesses as I got used to the damn stuff.
Good luck, let me know how it works out for you...my best advice is just to make sure you eat it with a LOT of food...like make sure you have it with your dinner. I have a sensitive stomach and if I don't have a full stomach I get sick.
Mel