My 22 year old cat is gaining weight with a couple of drops added to his water. I had forgotten to put it in a few days and he stopped eating his whole serving of food, and losing weight. Put it back in his water, and he is gaining again. I really think it is helping him fight whatever "autoimmune problem" (the vet gave this diagnosis)- he is having that the vet treats with prednisone. I haven't given him any prednisone in months, because he ran out, and the vet seemed to think that it was causing other problems like excessive thirst and urination...and I do too. His blood work did not show kidney failure. Anyway, the Iodine helps him in some way. Been giving it to him about a month, and will continue.