I've been using Alnutrin for a little over a year now. I use the little pre-measured packets of Alnutrin. It also comes in a container and you just weigh out the correct amount to use. I'm not sure what caused the constipationHow long have you been using Alnutrin? I'm in the process of changing my cats from dry to wet. I eventually want to go with raw and was interested in the Alnutrin supplement. How do you like it?