Best wet food for hyperthyroid senior cats

A 16-year-old Siamese with diet-managed hyperthyroidism — that's a cat who needs some real thought put into their food. Wet food is genuinely the right call here: cats are poor drinkers by nature, and kidney function often becomes a concern alongside hyperthyroidism in older cats, so the extra hydration matters a lot. Cost and convenience are real factors too, but in your situation the health case for wet is strong. Before I point you toward something specific, a couple of quick questions: is the hyperthyroidism being managed through a low-iodine prescription diet like Hill's y/d, or through medication with diet as a supporting factor? And how is her appetite and weight holding up at the moment?

That's really helpful — and it changes the picture quite a bit. Since she's on methimazole rather than a low-iodine diet, you're not locked into a prescription-only food, which gives you more options. The muscle loss at 3kg is the thing I'd focus on. Older cats, especially post-hyperthyroid ones, really struggle to maintain lean mass, so you want something with high-quality protein, good moisture, and reasonable calorie density. Is she a fussy eater? Siamese often are. And does she eat pâté-style textures, or does she prefer chunks in gravy or jelly?

Perfect, that narrows it right down. For a lean, muscle-depleted senior cat who needs high protein, good hydration, and smooth texture — and who isn't on a low-iodine restriction — I'd go with Royal Canin Ageing 12+ wet food in the mousse format. It's specifically formulated for cats over 12, with adapted protein levels to support muscle maintenance, enhanced with EPA and DHA for joint and kidney support, and the mousse texture is very consistent so fussy cats tend to accept it well. The poultry base also means it sidesteps that strong fishy smell she objects to. It's available in multipacks on Amazon UK and works out reasonable per pouch. Given her age and the hyperthyroid history, I'd still run the choice past your vet at her next check — not because there's anything wrong with it, but because they may want to monitor kidney values as her diet shifts.

At 3kg she's on the lighter side, so the standard feeding guides will likely overshoot. Royal Canin's guideline for a 3kg cat is around 2 to 3 pouches a day (each pouch is 85g), but for a lean elderly cat I'd start at 2 pouches and assess over two to three weeks — you're looking for very slow, steady weight gain rather than any rapid change. Split across at least two meals, ideally three if she'll tolerate the routine, since smaller older cats often do better with smaller, more frequent servings. If she's still losing weight on 2 pouches, move to 3. And keep fresh water available separately from her food bowl — cats drink more when the water isn't right next to where they eat.

The main one is kidney function. Hyperthyroidism can actually mask early kidney disease by artificially raising blood flow to the kidneys — so once it's well-controlled with methimazole, kidney problems sometimes become more visible. It's not a reason to panic, but it is worth asking your vet to run kidney bloodwork every six months if they're not already doing so. Beyond that: dental health affects appetite a lot in older cats so check her mouth if eating slows down, and watch for any sudden weight loss or increased thirst, which can signal the thyroid levels shifting. She sounds well looked after — at 16 with a managed condition and a careful owner, she's in good shape.