> but be aware that recent studies of these products suggests there could be an element of placebo effect going on
Wasn't the 'placebo' effect found in a study on humans with knee 'pain', where people
said how much pain they did or did not have prior to and after suppliments, rather than any increase in actual mobility being measured?
In my experience, my pups pain wasn't a matter of 'is he or isn't he in pain', he actually could not walk further than about 4 yards before he legs went form under him. I find it hard to understand how he could have had a placebo effect of actually being able to walk properly and even run & play, but that's just my opinion from my own experience.
Glucosamine itself, is not going to cause calcified deposits in the joints like over-supplimenting with calcium will (for example) and will not have an adverse cumulative effect, it can however cause a simple upset stomach if the dog is given to much in a single dose.
As I said in my earlier post, it's
always best to check with the vet first - for ANY suppliment, as some things that are often included with many seemingly innocent suppliments may have contra-indications for certain problems and/or with some medications (eg. willow bark is contra-indicated in those taking NSAIDS etc...)