Cat weight loss – what can it mean and when to see a vet?

Updated 2026-09-30 · 1 sources

Based on: PDSA

Book a vet visit

This is not usually an emergency on its own – contact your vet if it lasts, gets worse or your cat seems unwell in any other way. Weight loss in cats is usually a sign of a problem and can have causes ranging from minor to serious.

What to do now

What you can do now

Contact your vet.
Note when it started, how often it happens and what else you see.
Take a photo or short video to show the vet.
Keep fresh water available.

Don't

Do not give any human medicine.
Do not wait if it gets worse.

What it can mean

Weight loss in cats is usually a sign of a problem.^[1] It can be caused by many different problems, ranging from minor to serious.^[1] Gradual weight loss can be tricky to spot, especially if your cat is fluffy.^[1]

Other signs that can come with it

Eating more
Eating less
Vomiting
Diarrhoea
Peeing or drinking more than usual
Low energy
Poor coat condition
Loss of muscle

Possible causes

Worms
Dental disease
Hyperthyroidism
Stress
Lack of food
Kidney disease
Diabetes
Other illness
Eating less than usual
Another pet eating their food

What the experts say

“Overview. Weight loss in cats is usually a sign of a problem. Rapid weight loss is easy to spot but gradual weight loss can be tricky, especially if your cat is fluffy. Weight loss can be caused by many different problems, ranging from minor to serious.”
— PDSA [1]

If your pet is struggling to breathe, has collapsed, is having a seizure or can't stand up: go to the nearest vet now.

Not sure how serious it is?

OkPaw asks a few quick questions about your pet and tells you in 30 seconds whether it can wait. Free on Google Play for Android.

OkPaw is on Android now – an iPhone version is on its way.

Common questions

Can gradual weight loss be hard to notice?

Yes, gradual weight loss can be tricky to spot, especially if your cat is fluffy.^[1]

What can cause weight loss in cats?

Possible causes include worms, dental disease, hyperthyroidism, stress, lack of food, kidney disease, diabetes and other illness.^[1]

What other signs can come with weight loss?

Other signs can include eating more or less, vomiting, diarrhoea, peeing or drinking more than usual, low energy, poor coat condition and loss of muscle.^[1]

Sources

PDSA

How this page was made: written with the help of AI from the sources below, then checked claim by claim against those sources. Urgency levels follow OkPaw’s fixed safety rules. It is guidance, not a diagnosis. How we write our pages

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