Diabetes in Cats: Signs, Treatment and Living With It

At a glance

What it is	A condition where the body doesn't make enough insulin or doesn't respond to it properly, so blood sugar stays too high
Who's at risk	Mainly middle-aged and older cats, especially those who are overweight, inactive or neutered males
Main signs	Drinking and peeing more, weight loss, increased appetite, weakness in the back legs or walking on the hocks
Contagious?	No
Can it be prevented?	Not always, but keeping your cat at a healthy weight lowers the risk

What it is

When your cat eats, food is broken down into sugar (glucose), which travels in the blood to give the body's cells energy. A hormone called insulin, made by the pancreas, acts like a key that lets sugar into the cells.

In diabetes mellitus, this system stops working properly. In cats, the most common form is similar to type 2 diabetes in people: the body becomes less responsive to insulin and the pancreas struggles to keep up. Sugar builds up in the blood while the cells are effectively starved of energy. The body then breaks down fat and muscle for fuel, which is why cats lose weight even when they're eating well.

When blood sugar is very high, the kidneys can't hold it all back, so sugar spills into the urine and draws water with it. That leads to more peeing and, in turn, more drinking.

Several things raise the risk. Being overweight is one of the biggest, because extra body fat makes the body less sensitive to insulin. Age, inactivity, some other illnesses, certain long-term medicines and possibly some breeds also play a part.

Signs to watch for

Signs often develop gradually. Keep an eye out for:

• Drinking more. Water bowls emptying quickly, or your cat seeking out new water sources.
• Peeing more. Heavier litter trays, larger clumps, or accidents outside the tray.
• Weight loss. Often in spite of a good appetite.
• Increased appetite. Your cat may seem hungrier than usual.
• Walking on the hocks. Some diabetic cats develop weakness in the back legs, so they walk or stand with their hocks (the "ankle" joint) lowered towards the ground. This is caused by nerve changes linked to high blood sugar.
• A poor coat and lethargy. Grooming less and sleeping more.

Several of these signs overlap with other conditions common in older cats, such as kidney disease and hyperthyroidism. Our article on why a cat may be drinking more explains the possibilities, and the symptom checker can help you gather your thoughts before you call your vet.

• 💧

  Drinking more

  Emptying the water bowl faster than usual.

• 🚽

  Peeing more

  More or bigger wees, accidents, heavier litter clumps.

• 🍽️

  Eating more

  Hungrier than usual — sometimes ravenous.

• ⚖️

  Losing weight

  Despite eating well, often the most surprising sign.

When to see a vet

Book an appointment soon if your cat is drinking or peeing more, losing weight or seems hungrier than usual. Early diagnosis matters with diabetes, as starting treatment promptly may give the best chance of good control and, for some cats, remission.

Contact a vet urgently if your cat:

• stops eating, especially if they have also been drinking a lot
• is vomiting, very lethargic or weak
• has breath that smells sweet or like nail-polish remover
• is breathing fast or seems distressed

These can be signs of a serious complication called diabetic ketoacidosis, which needs emergency treatment.

Low blood sugar is an emergency

If your cat is already on insulin, it's vital to know the signs of low blood sugar (hypoglycaemia). These include sudden weakness, wobbliness, trembling, unusual quietness or confusion, twitching, seizures or collapse. If you see any of these, contact your vet or an emergency clinic straight away. Your vet will explain in advance what first-aid steps they'd like you to take while you get help, so ask about this when your cat starts treatment.

How vets diagnose it

Your vet will ask about your cat's signs and examine them, including checking weight and body condition. Diagnosis is usually based on:

• Blood tests, which show whether blood sugar is persistently high and check other organs.
• Urine tests, which look for sugar and ketones (a by-product of fat breakdown) in the urine, and check for infection, which is common in diabetic cats.

Cats can have a temporary rise in blood sugar simply from the stress of a vet visit. Because of this, your vet may run an additional blood test that reflects average blood sugar over the previous couple of weeks. This helps confirm whether diabetes is really present.

Your vet may also look for other conditions that can affect diabetes, as treating these can make blood sugar easier to control.

Treatment and management

Most diabetic cats need insulin injections, usually given at home under the skin. That can sound daunting, but the needles are very fine and most cats barely notice them, especially when injections are paired with a meal or a fuss. Your vet team will show you exactly how to store, prepare and give insulin, and will set the type and amount for your cat. Never change the dose yourself without speaking to your vet.

Alongside insulin, your vet is likely to recommend:

• A suitable diet. Many vets suggest a diet that is high in protein and low in carbohydrate, often a prescription food. Feeding at consistent times helps keep blood sugar steady.
• Gradual weight loss for overweight cats. Slow, steady weight loss under vet supervision can greatly improve how the body responds to insulin. Crash diets are dangerous for cats, so always follow a vet-guided plan.
• Treating other problems. Infections, dental disease and other conditions can make diabetes harder to control.

Remission

Some cats, particularly when diabetes is diagnosed and treated early and their weight is well controlled, can go into remission. That means they no longer need insulin, at least for a while. Remission isn't guaranteed, and diabetes can return, so ongoing monitoring and a healthy weight stay important. Your vet can tell you whether remission is a realistic goal for your cat.

Prevention

Not every case can be prevented, but you can lower the risk:

• Keep your cat at a healthy weight. This is the single most helpful step. Our article on obesity in pets and the tools on our pet calculators page can help you understand your cat's body condition and feeding.
• Encourage activity. Play sessions with wand toys, puzzle feeders and climbing spaces help keep indoor cats moving.
• Have regular check-ups, particularly as your cat gets older.

Living with it

Caring for a diabetic cat takes routine, but many owners find it becomes second nature within a few weeks.

• Keep a regular schedule. Feed and give insulin at the same times each day, as your vet advises.
• Monitor at home. Your vet may teach you to check blood sugar at home using a small sample from the ear, or suggest monitoring devices or urine testing. Note water intake, appetite, litter tray habits and weight in a diary.
• Weigh your cat regularly. Monthly weigh-ins help you and your vet track progress.
• Plan ahead. Make sure you have enough insulin and supplies, and arrange trained cover if you go away.
• Go to recheck appointments. Your vet will adjust treatment based on how your cat is doing, especially in the early weeks.
• Know the warning signs of low blood sugar, and keep your vet's and the nearest emergency clinic's numbers handy.

With good teamwork between you and your vet, most diabetic cats go on to enjoy a comfortable, happy life.