Can Hill's Y/D diet make my hyperthyroid cat lethargic?

The science diet Y/D is a good food for an over active thyroid. Changing the food is a good idea, but you should have the thyroid level checked every 4-6 weeks as some cats do not need the medication once the food is changed, some just need to change to dose. So checking the range frequently can let you know how in control it is

If you are feeding Hill's y/d diet, then yes, you can give it to all the cats. The cats that are not hyperthyroid though need iodine supplementation since the y/d diet is an iodine-restricted diet. This is VERY important. It is recommended that you take those healthy cats aside once a day and feed them a tablespoon (per cat) of regular canned cat food to increase their iodine intake. This should work just fine. Hope this answers your question. Best wishes!

Unfortunately the only food that will have a chance of working on its own it’s Hill’s. The other brands have not been formulated and studied with the same purpose. It is not the gold standard treatment for Hyperthyroidism but might work in some specific cases. Hyperthyroidism is caused by a tumour of the thyroid gland, and although benign can’t be left untreated. My personal recommendation would be to discuss other treatment options which might be more appropriate given Bob’s underlying allergies and given his relatively young age. Hope this helps !

if she is borderline and symptomatic they can send a thyroid test that can test more than just the in house version for a more definitive complete answer. Also they do make a food tailored to hyperthyroid cats that can help maintain the thyroid level. It is not safe to do if the number it not high though and it has to be the only food she gets. It is called science diet Y/D. I would talk to your vet about sending off a complete thyroid panel prior to any changes

You can add some chicken broth to it, but it's important to make sure that it is low sodium and does not contain any garlic or onion powder. Hill's also have a thyroid care wet food, and you can mix that in with the dry food to tempt Patches to eat it. I hope this helps :-)

Ideally her diet should be changed, there is a prescription diet for hyperthyroidism which is called Y/D and very good results can be achieved with it, so I would definitely recommend switching Priscilia to it as it can reduce the amount of Methimazole used.

She can eat just about anything she likes being hyperthyroid, as there are no specific diet recommendations for hyperthyroidism. As long as she continues her medication daily, then she can be on any senior diet food. that she likes. Some recommend high quality brands are Hill's Science Diet, Royal Canin, Eukanuba or Evo. Best of luck with your cat Stascha and her thryoid condition. Take care!