The most common signs of diabetes in cats and dogs are drinking much more water, peeing more, being hungrier than usual and losing weight even though they eat well. Cats may also start walking flat on their back legs, and dogs often develop cloudy eyes from cataracts. If your pet shows these signs, book a vet visit for a blood and urine test. If they are also vomiting, refusing food or very weak, go today.
The short answer
- The classic four: drinking more, peeing more, eating more and losing weight. Vets see this pattern in most diabetic cats and dogs.
- Cat-specific signs: walking on the hocks (back legs flat to the ground), jumping less, a greasy or flaky coat and bigger clumps in the litter box.
- Dog-specific signs: sudden cloudy or blue-white eyes (cataracts) and urinary tract infections that keep coming back.
- Who is at risk: overweight, older, neutered male cats and middle-aged dogs, especially unspayed females and breeds like Samoyeds and Miniature Schnauzers.
- Emergency: vomiting, not eating, weakness, sweet or acetone breath or fast breathing can mean diabetic ketoacidosis. See a vet the same day.
- Diagnosis: only a vet can confirm diabetes, with blood glucose, urine glucose and often a fructosamine test.
Diabetes symptom checker
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A planning aid based on common guidance, not a substitute for your veterinarian.
What diabetes does to a cat or dog
Diabetes mellitus happens when the body does not make enough insulin or stops responding to it. Without insulin, glucose from food cannot get into the cells, so it builds up in the blood. Once blood glucose passes a certain level, the kidneys can no longer hold it back and sugar spills into the urine, pulling water with it.
That one mechanism explains the classic signs. Sugar in the urine means more urine, more urine means more thirst, and cells starved of fuel make the body break down fat and muscle while the brain keeps asking for more food. The AAHA Diabetes Management Guidelines list polyuria, polydipsia, polyphagia and weight loss as the four classic signs in both species.
Dogs usually develop a form similar to type 1 diabetes in people, where the insulin-making cells are lost and lifelong insulin is needed. Cats usually develop a form closer to type 2, linked to obesity and insulin resistance, which is why some cats can go into remission.
Diabetes symptoms in cats and dogs at a glance
| Sign | Cats | Dogs | What it looks like at home |
|---|---|---|---|
| Drinking more (polydipsia) | Very common | Very common | Water bowl empties faster, pet drinks from taps, sinks or the toilet |
| Peeing more (polyuria) | Very common | Very common | Bigger litter clumps, accidents indoors, asking out at night |
| Increased appetite (polyphagia) | Common | Common | Begging, finishing meals instantly, stealing food |
| Weight loss despite eating | Very common | Very common | Spine and hips easier to feel, muscle loss over the back |
| Walking on the hocks | Typical of cats | Rare | Back legs flat to the ground, struggling to jump onto furniture |
| Poor coat and dandruff | Common | Less common | Greasy, matted or flaky fur, less grooming |
| Cataracts | Rare | Very common | Eyes turn cloudy or blue-white within weeks, bumping into things |
| Recurrent urinary infections | Possible | Common | Straining, blood in urine, infections that come back |
| Lethargy | Common | Common | Sleeping more, less interest in play or walks |
Early signs of diabetes in cats
The early signs of diabetes in cats are easy to miss because cats hide illness well and many drink from places you cannot measure. Watch for these changes:
- Bigger and more litter clumps. Clumps the size of a fist, or a litter box that needs changing far more often, deserve a vet visit.
- More time at the water bowl. A cat that suddenly drinks from the tap, the shower or a glass on the table may be thirsty for a reason. Our guide to how much water a dog or cat should drink explains what is normal and how to measure it.
- Weight loss in a cat that eats well. A cat that was overweight may lose weight and you may feel relieved at first. If they eat as much or more than before, that weight loss is a warning sign. A cat weight chart by breed helps you track the trend.
- A poor coat. Diabetic cats often groom less, so the coat looks greasy, matted or flaky, with dandruff along the back.
- Walking on the hocks. High blood sugar can damage the nerves in the back legs (diabetic neuropathy). The cat stands and walks with the hocks, the heel area of the back leg, close to the ground, a posture vets call a plantigrade stance. Earlier on you may only notice that your cat jumps less or misses jumps.
Many of these overlap with other illnesses, especially kidney disease and an overactive thyroid in older cats. Our guide to signs your cat is sick covers the wider picture.
Signs of diabetes in dogs
Dogs show the same classic four signs, often more obviously than cats: you see them drink, and they need to go out at night or have accidents indoors.
- Cataracts. This is the sign that most often brings diabetic dogs to a vet. Excess glucose in the eye pulls water into the lens, which turns cloudy, sometimes within days or weeks. Around three quarters of diabetic dogs develop cataracts within a year of diagnosis. Cataracts are rare in diabetic cats.
- Recurrent urinary tract infections. Sugar in the urine feeds bacteria. A dog with repeated infections, straining or blood in the urine should be checked for diabetes.
- Tiredness and weakness. Dogs may walk less, sleep more and seem flat. Dogs often hide discomfort, so our guide to signs your dog is in pain is worth a look if your dog just seems off.
Already managing diabetes? PetVitals logs glucose readings and insulin doses, charts the curve and builds a PDF for your vet.
Risk factors
Cats
- Obesity. The biggest modifiable risk. Cornell Feline Health Center notes that obese cats are up to four times more likely to develop diabetes than cats at an ideal weight.
- Age. Most diabetic cats are middle-aged or older, typically over 7 to 8 years.
- Male, neutered cats. Males are affected more often than females.
- Physical inactivity. Indoor cats that move little are at higher risk.
- Steroid use. Long-term glucocorticoids (and some progestogen drugs) cause insulin resistance and can trigger diabetes.
- Breed. Burmese cats have a higher risk in the UK, Europe and Australia, although this may not hold in the United States.
Dogs
- Age. Most dogs are diagnosed in middle age, around 7 to 10 years.
- Unspayed females. Progesterone during the heat cycle and pregnancy causes insulin resistance. Intact females are affected about twice as often as males.
- Breed. Samoyeds, Miniature Schnauzers, Miniature and Toy Poodles, Australian Terriers, Bichon Frises, Keeshonds and Fox Terriers are overrepresented.
- Pancreatitis. Repeated or chronic inflammation can destroy the insulin-making cells.
- Cushing's disease and steroids. Excess cortisol, whether from the adrenal glands or from medication, causes insulin resistance.
- Obesity. It makes control harder and is linked to pancreatitis.
Emergency signs: diabetic ketoacidosis
When there is not enough insulin, the body burns fat for fuel and produces ketones. If ketones build up, the blood becomes acidic. This is diabetic ketoacidosis (DKA), and it is a life-threatening emergency. It is sometimes the first sign of diabetes in a pet nobody knew was diabetic, and it can also happen in a known diabetic during illness or missed insulin.
Diabetic ketoacidosis cat symptoms and dog symptoms are similar:
- Vomiting, or refusing food for more than a day
- Lethargy, weakness or wobbliness
- Dehydration, such as tacky gums and skin that is slow to spring back
- Sweet, fruity or nail-polish-remover (acetone) breath
- Fast or deep breathing
- Belly pain, collapse or confusion
If your pet has diabetes signs and any of the signs above, go to your vet or an emergency clinic today. DKA needs hospital treatment with fluids and insulin, and waiting overnight can be fatal.
Cats on the newer oral diabetes tablets (SGLT2 inhibitors such as bexagliflozin and velagliflozin) can develop DKA even when their blood glucose looks normal. If a cat on these drugs stops eating, vomits or becomes lethargic, call your vet the same day.
How vets diagnose diabetes
Diabetes is not diagnosed from signs alone. Kidney disease, an overactive thyroid, Cushing's disease and other conditions can cause thirst and weight loss too. A vet will usually:
- Measure blood glucose. Persistently high blood glucose is the key finding.
- Test the urine. Glucose in the urine (glucosuria) confirms that sugar is spilling over. The urine is also checked for ketones and infection.
- Check fructosamine. This blood test reflects average glucose over the previous one to two weeks, so a single stressful moment does not raise it.
- Run a wider blood panel. This looks for pancreatitis, kidney disease, thyroid disease and other conditions that affect treatment.
Stress hyperglycemia in cats is a common trap. A frightened cat at the clinic can have a blood glucose high enough to look diabetic. That is why vets look for glucose in the urine as well, often on a sample collected at home after the cat has settled, and use fructosamine to separate real diabetes from a stressful car ride.
What happens after a diagnosis
Most diabetic cats and dogs live good lives with treatment.
- Insulin. Most dogs and many cats need insulin injections, usually once or twice a day with meals. Some newly diagnosed, otherwise healthy cats may be offered an oral SGLT2 inhibitor instead.
- Diet. Cats do best on a high-protein, low-carbohydrate diet, often wet food. Dogs need consistent meals at the same times, matched to insulin doses, often with higher fiber.
- Weight control. Bringing an overweight pet to a healthy weight improves insulin sensitivity.
- Home monitoring. Many owners learn to check blood glucose at home or use a continuous glucose monitor. Daily notes on water intake, appetite, urine and insulin doses help your vet fine-tune treatment. Our guide to tracking blood glucose and insulin at home walks through glucose curves, target ranges and what to log.
- Spaying. For an intact female dog, spaying removes the progesterone-driven insulin resistance and is usually recommended.
Remission in cats
Cats can go into diabetic remission, meaning they no longer need insulin. The AAHA guidelines report remission rates from about 15% to 100% depending on the study. The best chances come with early diagnosis, good glucose control within the first six months, a low-carbohydrate diet, weight loss, stopping steroids where possible and long-acting insulin such as glargine or detemir. Remission is rare in dogs.
Remission is not a cure. Cats in remission need ongoing weight control and checks, because diabetes can return. Careful monitoring matters here too: a cat heading toward remission needs less insulin, and missing that change risks a dangerous low. Logging every reading is how you and your vet spot it, which is why we recommend tracking blood glucose and insulin at home from the first week.
When to see a vet
- Today: diabetes signs together with vomiting, not eating, weakness, sweet breath or fast breathing.
- Within a day or two: two or more of the classic signs, especially drinking and peeing more with weight loss.
- Soon: cloudy eyes in a dog, repeated urine infections, or a cat that has started walking on its hocks.
Catching diabetes early makes treatment easier and, in cats, gives the best chance of remission. Bring notes on what you have seen to your vet.