3 Silent Signs Your Cat's Kidneys May Already Be in Trouble(And Why Vets Wish You'd Spotted Them Sooner)

By the time most owners notice, the damage is done. Here's what the early signs look like — and what feline specialists actually do about them.

Updated 25 June 2026

Read time: 4 mins

Written by Megan Williams.

Cat lover of 20 years

There's a reason kidney disease is called the silent killer of cats.

Title

A cat can be in real trouble and still eat, purr, and sleep in the sun looking completely normal — they're wired to hide weakness. By the time the obvious signs arrive, the kidneys have often lost a large share of their function, and the filtering units that quietly clean her blood don't grow back. What's gone is gone.

 

Chronic kidney disease (CKD) affects an estimated 1 in 3 cats over the age of 10, and it's one of the leading causes of death in senior cats.

 

So here are three changes worth watching for. None of them proves kidney disease on its own — other conditions cause them too — but all three are the kind of quiet shift owners notice, shrug off as "she's just getting older," and mention to the vet a year too late. Read to the end — the third is the one almost everyone explains away.

1. She's drinking more — and you've stopped noticing

This is one of the earliest signs, and the easiest to miss. As kidneys lose the ability to concentrate urine, the cat compensates the only way she can: drinking more, weeing more. A water bowl that empties faster. A heavier litter tray. A cat suddenly fascinated by the bathroom tap.

 

It creeps up so gradually that you adjust without registering it. If you've quietly been refilling the bowl more often than you used to — that's not nothing. A simple blood and urine test can tell you whether it's kidneys, thyroid, diabetes, or nothing at all. The test is the whole game.

2. The weight is coming off her spine, not her belly

Run your hand down your cat's back right now. If the spine and shoulder blades feel sharper than they did six months ago, pay attention.

 

Kidney trouble can quietly strip muscle from the back and hindquarters while the cat is still eating normally — which is precisely why owners miss it. The scale drifts down a few hundred grams at a time, slow enough that "she's an old lady now" feels like an explanation. Often it isn't. Unexplained muscle loss in a senior cat is one of the changes vets most want to hear about, and the longer it's read as ordinary ageing, the more ground you lose.

3. She's eating differently — even if she hasn't stopped

This is the one everyone explains away. She leaves half her dinner. She sniffs the bowl and walks off, then wants treats an hour later. She's just "fussy" now.

 

Appetite changes can show up well before a cat looks unwell, because circulating toxins from struggling kidneys quietly make her feel off. It isn't proof of CKD — dental pain, nausea and thyroid disease cause the same thing — but a senior cat who's changed how she eats is a cat whose owner should be at the vet, not on a forum deciding she's just become picky.

Omega-3 is HIGHLY RECOMMENDED by vets for cats with CKD.

A veterinary renal diet is the foundation for cats with CKD. It manages phosphorus, protein, sodium and other nutrients all at once — and many renal diets also include marine omega-3s, EPA and DHA, by design.

 

That is because EPA and DHA help reduce inflammatory compounds and oxidative stress that can place extra strain on already-compromised kidneys. In feline research, renal diets higher in omega-3s have been associated with better outcomes, while an early DHA study in cats with CKD showed encouraging kidney-related signals [PubMed, 2022]. 

 

EPA and DHA are delicate fats, and their levels can decline during heat processing and long-term storage — another reason consistent marine omega-3 intake matters.

 

They are not a cure, and they do not replace a renal diet. But they are not a “nice extra” either. They are one of the most important nutritional pieces vets consider when supporting a cat with kidney disease.

The problem is that fish oil only works when the cat actually gets it — consistently. Open bottles sit around for weeks. Capsules stay in drawers. And picky senior cats often reject fish oil before it ever reaches the bowl. 

Where Fureeze fits

We built Fureeze to kill that friction — not to replace your vet's plan, but to make the omega-3 part something you'll actually keep up.

 

Every dose comes in an individually sealed sachet of marine fish and krill oil, helping protect it from air exposure between serves. No open bottle sitting in the fridge, no measuring, and no capsules to wrestle into a picky cat. 

 

Each sachet delivers 278mg of combined EPA + DHA in a consistent, pre-measured daily dose. You tear it, pour it over her food, she finishes it. Made for senior cats whose owners want the omega-3 routine handled.

Whether your cat already has CKD or you’re looking after an ageing cat before a diagnosis, Fureeze delivers daily EPA + DHA—omega-3s used in kidney-support diets to help slow CKD progression and support long-term kidney health.

️🎊 Mid Year Sale ️🎊

00
DAY
00
HRS
00
MIN
00
SEC

ACT Now And Receive
50% Off Your Order

TRY FUREEZE

HIGH Risk of Sell-out

|

FREE shipping

Try it today with a 90-Day Money Back Guarantee!

What UK and US cat parents are saying

TRY FUREEZE

Megan Williams is an UK-based writer and lifelong cat owner. This article includes affiliate links; Fureeze provided product for review but did not approve the final copy. 

Title

© 2026