Went to see Matthew Wood at Rosemary's Garden in Sebastopol Friday night and he recommended Melissa, also known as lemon balm, for thyroid issues in cats. Not tincture, since cats won't take anything with alcohol (they are smarter than their humans). Make a strong tea then "get them to drink it." I usually do this with a plastic eye dropper in the side of the mouth towards the back. I have never found a better way that works to get cats to take liquid medicines. If you know of one, let me know.
Since Grace has thyroid problems, I plan to try it this week. She was on medication, but it made her vomit constantly and since she is so thin already, I want her to keep whatever food she has eaten. I have found that one of her favorite things is raw chicken liver. It is a little more expensive than cat food, but I don't have to keep throwing it out.
You know I keep telling both Grace and Melody (two formerly feral cats) that they eat better than most people in the world, but they still turn their noses up at most cat food. Very challenging sometimes.