Carbjunky,
A bit late I know, your post must have passed me by. Not sure about carbs in glucosamine, but they have no impact on my bg. It was my doctor that told me to start taking glucosamine for a similar problem as yourself, he said to take a high dose 0f 1500mg to get max benefit.
As my doctors advice was intended for myself, I would check with your doctor and make sure it is safe for you to use, as I don't know what meds you are on or your previous medical history.
Nigel