Diabetes in cats: Causes, symptoms and treatment

Jul 15, 2022

What is diabetes in cats?

Diabetes is a condition which prevents your cat’s body from either properly producing or responding to the hormone, insulin.

Like the human body, the cells in a cat’s body need sugar in the form of glucose for energy. However, glucose in the blood requires insulin, a hormone produced by the pancreas, to “unlock” the door to cells. Insulin attaches to cells and signals when the time is right to absorb glucose. By absorbing glucose, cells in fat deposits, the liver, and muscles get vital fuel while lowering levels of glucose in the blood.

Type I vs. Type II diabetes in cats

The following are the differences in both Type I and Type II diabetes:

  • In Type I diabetes, blood glucose concentrations are high because of a decrease in insulin production.
  • In Type II diabetes, glucose levels are high because cells in the body do not respond appropriately to insulin.
  • In both Type I and Type II diabetes, cells cannot access the nutrients they need even though there is plenty of sugar in the blood. That’s  because insulin isn’t transporting the sugar from the bloodstream into the cells.

Cats with diabetes most commonly suffer from the Type II form of the disease. The Cornell University College of Veterinary Medicine states that feline diabetes is rare, with an estimated 0.2% and 1% of cats being diagnosed with diabetes during their lifetime. Common risk factors include obesity, age, a sedentary lifestyle and the use of steroids to treat illnesses including feline asthma. Male cats are more prone than female cats to diabetes.

What are the symptoms of diabetes in cats?

Weight loss

A common sign of diabetes is a sudden, dramatic weight loss, even though your cat is still chowing down with gusto. Increased thirst and urination are also indicators of the condition, so observe your cat’s litter box and water bowl closely.

Diabetic weight loss occurs when the body’s cells are unable to efficiently absorb glucose from the blood, and become energy depleted. To feed the hungry cells, the body begins to break down fats and proteins as a source of nutrition.

Nerve damage

If diabetes is left untreated, your cat may experience nerve damage in the back legs, resulting in a slumped posture. This posture is called a “plantigrade” stance, and is generally not painful but can affect mobility. The good news: if caught early, the condition is often temporary and may resolve with treatment.

Increased drinking & urination

Drinking and urinating excessively are the result of high blood sugar levels. Elevated glucose in the bloodstream can overwhelm the processing capacity of the kidneys,  allowing it to spill over into the urine. The glucose then pulls extra water into your cat’s urine, resulting in larger urination volume, as well as extreme thirst and dehydration.

How is diabetes diagnosed in cats?

Your vet measures the glucose concentration in your cat’s blood and urine as the basis for a diabetes diagnosis. If both levels are very high, the diabetes diagnosis is clear-cut. More than one visit and specimen sampling are necessary when a cat has a mildly high blood glucose measurement. Cats may experience a temporary spike in blood glucose in response to stress, including a car trip and a vet visit. This is known as stress hyperglycemia.

Your vet will look for a consistent trend in your cat’s blood glucose readings. They may also recommend other tests in response to your cat’s clinical signs. Additional testing could include those that check for a urinary tract infection, chronic kidney disease, pancreatitis or hyperthyroidism.

What is the treatment for diabetes in cats?

Insulin Therapy

Although human diabetes may sometimes be effectively treated with oral medication, a feline counterpart is not currently available. There are multiple types of injectable insulin preparations to consider, including lente insulin (Vetsulin), ProZinc or glargine insulin.

Insulin varies in cost, duration of action, and concentration so be sure to discuss all options with your vet. It is also important to note that each insulin type requires a specific syringe size (U-100 or U-40), so make sure that you use the appropriate syringe for your pet.

An insulin regimen for your cat is an important commitment. Subcutaneous insulin injections (injections under the skin) are necessary approximately every 12 hours. Most cats are injected in the scruff of the neck, where the skin is thick, less sensitive and easy to lift up. It may seem daunting, but remember that most cats are accepting of this process and are not bothered by the very fine needle that is used.

Dietary changes for cats with diabetes

As with humans, a diet low in carbohydrates has been shown to improve blood sugar regulation in diabetic cats. Slow, steady weight loss for overweight cats is the goal. And your vet may recommend a change in foods. Several low carb diabetic prescription foods are available in both wet and dry form.

If you are giving your cat insulin shots, discuss the timing and frequency of your cat’s meals with your vet. The balancing act of blood glucose by insulin injections and food intake is a delicate one. Some of the decisions of when to feed your cat will depend upon the type of insulin you’re using (short-acting versus longer-acting). Either way, it’s important to keep your cat’s meals on a strict schedule.


Controlling and managing diabetes in your cat requires vigilance. Regular monitoring helps you and your vet to determine the ideal dosage of insulin for your cat. This will help to prevent complications such as hypoglycemia and diabetic ketoacidosis (DKA).

Hypoglycemia (extremely low blood glucose) is a risk when too much insulin is given for the cat’s current needs, or if it is given without a large enough meal. Hypoglycemia can make a cat very weak, seizure, or even cause death.

On the other hand, chronically elevated blood sugar causes DKA, releasing acids called ketones into your pet’s blood and urine. The high level of ketone bodies in the blood can cause severe illness, including kidney failure. Keeping your cat’s glucose in the sweet spot requires occasional monitoring.

Glucose curves

Monitoring includes regular assessments of your cat’s weight, water intake and appetite. Effectively monitoring blood glucose often involves taking a blood glucose curve. Your vet will perform your cat’s first blood glucose.

Perform a blood glucose curve by testing blood sugar right before an insulin injection, and then every few hours during the day. Determine the appropriate dose of insulin by performing a blood glucose curve every few weeks following the initial diagnosis. Once your cat’s diabetes is regulated, space out the timing of curves once your cat’s diabetes is regulated. In stable cats, perform blood glucose curves every 4-6 months as insulin needs can change over time. Consult your vet for more details.

Glucose curves at home

To reduce stressful vet visits on your kitty, learn to do a glucose curve at home. At home, the glucose curve is more accurate because it isn’t affected by the increased stress to your cat resulting from a vet visit.

Collecting a drop of blood from your cat’s ear or paw pad can be difficult at first, but gets easier with time and practice. A pet blood glucose monitor reads your cat’s blood glucose. Keep track of the blood glucose readings noting the time of each reading. It’s also helpful to track what your cat eats before and after receiving an injection. If you observe wild swings in the readings, do not alter your cat’s dosage on your own. Instead, consult with your vet on their recommendations.

What’s the prognosis for cats with diabetes?

The good news is that although there is no cure for feline diabetes, adequate home management can help your cat maintain a good quality of life for many years. Early diagnosis and aggressive treatment are sometimes successful in putting cats into remission, meaning that the animal can maintain normal blood sugar levels without insulin injections.

Starting therapy early and monitoring closely are key steps. If your cat has not entered remission six months after diagnosis, in spite of therapy and monitoring, it is likely that your cat will need insulin injections as a lifelong treatment.

It’s important to always remain vigilant when you’re the pet parent of a diabetic cat. Continue to monitor closely, since most cats will at some point require insulin therapy again.

Keep in mind that good nutrition and lots of play and enrichment activities help to keep your pet’s weight in the normal range and will better control diabetes in your cat.