Diabetes is one of the health conditions that cats owners should know about, because it affects quality of life, and it is easier to manage when it is caught early. This guide explains what diabetes is, the signs to watch for, what causes it, how it is diagnosed, how it is treated, whether it can be prevented, and how to live with a cat that has it. Every suggestion here is general guidance, not a prescription for an individual cat.
The signs are the focus of this guide. diabetes in an older cat is often harder to spot than in a young one, because its signs — drinking more, losing weight, slowing down, or being confused — are easily mistaken for normal ageing. This guide lists every sign to watch for, explains what each one means, and covers when a sign means a vet visit, not waiting. An older cat that is changing — drinking more, eating less, losing weight, or behaving differently — needs a vet check, not just more food or more rest.
What is diabetes in cats?
Diabetes — diabetes mellitus — is a condition where the body cannot use insulin properly, so sugar builds up in the blood instead of going into the cells that need it for energy. In dogs, diabetes is usually caused by the pancreas not making enough insulin; in cats, it is usually caused by the body not responding properly to insulin, often linked to weight and inactivity. Diabetes is a long-term condition, but it can be managed well with insulin, diet, and regular checks, and some cats can even go into remission, where they no longer need insulin — though that is not something to count on.
The rest of this guide covers the signs, the causes, how diabetes is diagnosed, how it is treated, whether it can be prevented, and how to live with a cat that has it. A cat with diabetes should be checked by a vet, because the right treatment depends on the individual cat, its age, and how advanced the condition is — and because some of the signs of diabetes can also be signs of other conditions, which need a vet to tell apart. The cat ideal weight calculator works out a target weight range, and the when is a cat considered a senior guide gives the senior thresholds by size.
Signs of diabetes in cats
The signs of diabetes in cats are listed below. Not every cat with diabetes will show every sign, and some cats will show only one or two — but any one of these signs, especially if it lasts more than a few days or gets worse, is worth mentioning to a vet. A cat that is bright, eating, drinking, and otherwise well between episodes is less likely to be seriously ill than a cat that is lethargic, off its food, or losing weight — but the only way to know is to check.
- Drinking much more water than usual, and urinating much more.
- Weight loss, even though the cat is eating normally or more than usual.
- A bigger appetite than usual, with weight loss at the same time.
- Lethargy, weakness, and a cat that seems tired or dull.
- Cloudy eyes in dogs, and weak back legs in cats, where the cat walks flat on its hocks.
- A dull coat, and a cat that looks generally unwell.
- Recurring infections, such as urinary infections or skin infections.
If two or more of those signs apply, or if one sign is severe — a cat that cannot urinate, cannot breathe, cannot stand, or has had a seizure lasting more than five minutes — see a vet the same day. Those are signs that need a vet, not waiting. Bring a note of when the signs started, how often they happen, and what the cat eats and drinks — that information helps the vet far more than a guess about the cause. The how to tell if your cat is overweight guide gives the hands-on check for weight, which matters for many of these conditions.
Causes and risk factors for diabetes
In dogs, diabetes is usually caused by the pancreas failing to make enough insulin, and it is more common in older dogs and in some breeds. In cats, diabetes is usually caused by the body not responding properly to insulin, and it is strongly linked to obesity and inactivity — an overweight, inactive cat is far more likely to develop diabetes than a lean, active one. Some medicines can trigger diabetes, and some other conditions, such as an overactive thyroid in cats or an inflamed pancreas, can bring it on. Diabetes cannot be caught from another cat, and it is not caused by eating sugar.
Some cats are more prone to diabetes than others, because of their genes, their breed, their size, or their age — but breed and age are not destiny, and a cat of any breed can develop diabetes. What an owner can control is weight, food, exercise, and vet checks: a cat at a healthy weight, with measured food and daily exercise, is less likely to develop diabetes and will cope better with it if it does. A cat that is overweight, that eats a poor diet, or that never sees a vet is more likely to develop diabetes and to have it found late, when it is harder to treat.
How diabetes is diagnosed
A vet diagnoses diabetes with a blood test and a urine test: the blood sugar is high, and sugar is present in the urine, where it should not be. The vet may also run other tests to check for the conditions that can bring diabetes on, and to check the kidneys, liver, and pancreas. A cat that is drinking and urinating much more than usual, and losing weight despite a good appetite, should be checked promptly — diabetes is easier to manage when it is caught early, and a cat that is left untreated can become seriously ill within days or weeks.
If you are worried about your cat, see a vet and mention diabetes by name, with the signs you have seen and when they started. Bring a note of what the cat eats, how much, and any medicines it takes, and whether it has had diabetes or a related condition before. A video of the signs, if it is safe to take one, helps the vet far more than a description — especially for seizures, limping, or breathing problems. Do not try to diagnose diabetes yourself, and do not buy medicines or special diets for it without veterinary advice, because the wrong treatment can make it worse.
Treatment and management of diabetes
Treatment is usually insulin, given by injection once or twice a day, plus a consistent diet and feeding routine. The dose is set by the vet and adjusted by regular blood sugar checks — the owner learns to give the injections at home, and the vet checks the dose regularly. Diet matters: a consistent amount of food, at the same times every day, so the insulin dose matches the food. In cats, a high-protein, low-carbohydrate diet is often recommended, and weight loss is important for an overweight cat. The owner must also watch for low blood sugar — a cat that is wobbly, confused, or collapsed after insulin needs sugar at once and a vet call.
Treatment is a decision made with the vet, weighing the cat's age, health, and quality of life against the treatment and its side effects. Some owners choose not to treat, and to keep the cat comfortable instead — and that is a valid choice, made with the vet, not on the basis of a web page. Whatever is decided, the treatment must be followed every day, at the same times, and the cat must be checked regularly, because diabetes changes over time, and the treatment needs to change with it. Do not stop a medicine suddenly, and do not change the dose without veterinary advice.
Living with a cat with diabetes
A cat with diabetes can live a full and happy life with the right care, but it needs a routine: insulin at the same times every day, food at the same times every day, and regular vet checks. The owner must learn to give injections, to watch for low blood sugar, and to keep a record of food, insulin, drinking, and weight. Travel, illness, and changes in routine all affect blood sugar, so they need planning with the vet. A cat with diabetes that is well managed is bright, active, and well — and a cat whose diabetes is not managed will become ill fast, so the routine matters every day, not just on good days.
Keep a routine: the same times for food, medicines, walks, and play, the same places for furniture, food, and water, and a calm, predictable home. Keep a note of appetite, drinking, weight, and behaviour, and mention any change to the vet promptly — a change that lasts more than a few days, or that gets worse, is worth a vet visit. Keep the cat at a healthy weight, with measured food and daily exercise at a level that suits its body, and keep vet checks regular: once a year as an adult, and twice a year as a senior. The senior cat diet guide covers feeding older cats, and the cat calorie calculator works out daily calories for any weight.
Signs of diabetes in older cats
An older cat with diabetes may show the signs gradually, over weeks or months, rather than all at once — which is why they are easy to miss. Keep a note of what changes, and when: drinking more, eating less, losing weight, sleeping more, or behaving differently. A change that lasts more than a few days, or that gets worse, is worth mentioning to the vet, because diabetes is easier to manage when it is caught early.
Can diabetes be prevented?
Diabetes cannot always be prevented, because much of it is about genes and age — but the risk can be reduced a lot by keeping the cat at a healthy weight and active. An overweight, inactive cat is far more likely to develop diabetes than a lean, active one, so measured food, treats under 10% of daily calories, daily play, and a monthly weigh-in are the best prevention there is. Do not give medicines that can trigger diabetes without veterinary advice, and mention any change in drinking or urination to your vet early, because diabetes is easier to manage when it is caught early.
Early checks matter most: have the cat checked regularly, so diabetes is found early, when treatment works best. Keep the cat at a healthy weight, with measured food and daily exercise, and mention any change in drinking, eating, weight, or behaviour to your vet early, because a change caught early is easier to treat than one left for weeks.
For related reading, see the cat ideal weight calculator, the cat body condition score chart, the how to tell if your cat is overweight guide, the senior cat diet guide, the cat calorie calculator, the when is a cat considered a senior guide.
Frequently asked questions
What is diabetes in cats?
Diabetes — diabetes mellitus — is a condition where the body cannot use insulin properly, so sugar builds up in the blood instead of going into the cells that need it for energy. In dogs, diabetes is usually caused by the pancreas not making enough insulin; in cats, it is usually caused by the body not responding properly to insulin, often linked to weight and inactivity. Diabetes is a long-term condition, but it can be managed well with insulin, diet, and regular checks, and some cats can even go into remission, where they no longer need insulin — though that is not something to count on.
What are the signs of diabetes in cats?
The most common signs are: Drinking much more water than usual, and urinating much more. Weight loss, even though the cat is eating normally or more than usual. A bigger appetite than usual, with weight loss at the same time. See the full list above for every sign to watch for, and see a vet promptly if two or more apply, or if one sign is severe.
What causes diabetes in cats?
In dogs, diabetes is usually caused by the pancreas failing to make enough insulin, and it is more common in older dogs and in some breeds. In cats, diabetes is usually caused by the body not responding properly to insulin, and it is strongly linked to obesity and inactivity — an overweight, inactive cat is far more likely to develop diabetes than a lean, active one. Some medicines can trigger diabetes, and some other conditions, such as an overactive thyroid in cats or an inflamed pancreas, can bring it on. Diabetes cannot be caught from another cat, and it is not caused by eating sugar.
How is diabetes diagnosed?
A vet diagnoses diabetes with a blood test and a urine test: the blood sugar is high, and sugar is present in the urine, where it should not be. The vet may also run other tests to check for the conditions that can bring diabetes on, and to check the kidneys, liver, and pancreas. A cat that is drinking and urinating much more than usual, and losing weight despite a good appetite, should be checked promptly — diabetes is easier to manage when it is caught early, and a cat that is left untreated can become seriously ill within days or weeks.
How is diabetes treated?
Treatment is usually insulin, given by injection once or twice a day, plus a consistent diet and feeding routine. The dose is set by the vet and adjusted by regular blood sugar checks — the owner learns to give the injections at home, and the vet checks the dose regularly. Diet matters: a consistent amount of food, at the same times every day, so the insulin dose matches the food. In cats, a high-protein, low-carbohydrate diet is often recommended, and weight loss is important for an overweight cat. The owner must also watch for low blood sugar — a cat that is wobbly, confused, or collapsed after insulin needs sugar at once and a vet call.
When should a cat with diabetes see a vet?
See a vet promptly if the cat shows any of the signs above, especially if they last more than a few days or get worse — and the same day if the cat cannot urinate, cannot breathe, cannot stand, has had a seizure lasting more than five minutes, or is lethargic or off its food. Bring a note of when the signs started and what the cat eats and drinks. A cat with diabetes should be checked by a vet, because the right treatment depends on the individual cat, its age, and how advanced the condition is.
Results on this page are estimates for general information only and are not veterinary advice. If your pet is ill, underweight, overweight, pregnant, or has a health condition, consult your veterinarian before changing diet or care.