My 16 yo cat is on medication for hyperthyroidism, Without it she drops weight like a rock, has a poor appetite, sleeps a lot, and her hair looks dull and mats easily.
With it she holds a little bit of weight, has a very good appetite, is annoyingly friendly but slightly senile, has shiny fur, but she sheds it in huge clumps and is going bald along her spine.
Anyone else?