I've been giving this to my 69lb Lab for two weeks.  My vet prescribed Glucosamine-only tablets, any brand was fine.  Though my dog's arthritic limping was to improve in about 30 days of use, according to my vet when using 1500mg/day, after two weeks I am noticing an improvement.  This isn't to say that this product is the result of the improvement exclusively, but that it seems to be doing what it is supposed to do.  However, the price is (or was) very near what you might pay in a large club-type store, such as BJ's.