Diabetes mellitus in dogs: Symptoms, diet and treatment

A diagnosis of diabetes in your beloved canine companion can understandably seem like a scary prospect. Daily injections, prescription diets, regular blood glucose testing – oh my!

However, while supporting a diabetic pup can be a significant financial and time commitment, rest assured that most owners become comfortable managing their pet’s new health condition surprisingly quickly, particularly if they’re thoroughly prepped early on with some practical tips.

So, here’s your vet-prescribed injection of easy-to-digest knowledge on all things canine diabetes, including how it’s recognised, how it’s treated, and common pitfalls to avoid. Sweet!

What is diabetes in dogs?

After eating, glucose (sugar energy) passes from the digestive tract into the bloodstream. In healthy pets, the hormone insulin then acts like a key, “opening the door” to allow glucose to pass effectively from the bloodstream into cells of the body, where it is used for immediate energy or stored.

Diabetes mellitus (often just referred to as diabetes) is when a pet has insufficient insulin for their body’s needs. This results in glucose remaining trapped in the bloodstream, accumulating to high levels until it starts to spill out as waste into the urine. This means that while the pet has glucose in their body, they can’t properly utilise it, so they are starved of this vital energy source.

The majority of diabetic dogs have Type I diabetes, which means that their pancreas does not produce enough insulin. This can occur due to an autoimmune condition damaging their pancreas or secondary to other diseases such as severe pancreatitis (inflammation of the pancreas).

In cats, the most common type of diabetes is Type II diabetes, which involves abnormal insulin secretion and/or a poor responsiveness to insulin within their body.

Recognising diabetes in dogs: Symptoms to watch for

Dogs with diabetes mellitus commonly show symptoms of:

• An increased appetite
• Weight loss
• Increased thirst
• Increased urination

Weight loss despite a ravenous appetite occurs because the pet’s body is starved for energy (being unable to properly utilise the glucose obtained from food), so it is forced to break down fat stores and muscle as alternative energy sources.

Increased urination occurs because all the excess, unused glucose spilling into the pet’s urine acts like a sponge, drawing water along with it. The pet then loses a lot of body water and needs to drink more to maintain hydration.

Diabetic pets may also show more vague symptoms, such as reduced energy or poor coat condition.

Lastly, insufficiently managed diabetic dogs are at risk of tipping into a potentially life-threatening state of metabolic imbalance known as diabetic ketoacidosis. This causes symptoms such as lethargy, vomiting, diarrhoea, and a poor appetite, and can lead to severe dehydration, electrolyte imbalances and organ damage.

How diabetes in dogs is diagnosed

Your vet will suggest running blood tests on your dog to check for diabetes if they are demonstrating any of the common associated symptoms (increased appetite, unexplained weight loss, increased drinking, or increased urination). Sometimes, however, diabetes is detected on general blood tests performed on a pet who’s just “not quite right”!

The initial testing for diabetes usually involves blood tests to check your dog’s glucose levels. Your pet should ideally be fasted (have food withheld for 8-12 hours) prior to testing for the most accurate result.

If your dog is found to have abnormally high blood glucose levels, your vet may wish to assess them further by sending off a blood sample for fructosamine testing. This test indicates your pet’s average blood glucose levels over the preceding 2-3 weeks, so can help your vet check that your dog’s initial blood glucose levels weren’t just elevated as a “on-off” due to stress in the veterinary hospital.

If your dog is diagnosed with diabetes, your vet will likely discuss additional health screening tests such as:

• Blood tests to assess your pet’s general health (such as their liver and kidney parameters).
• Urine testing to screen your pet for a urinary tract infection, which dogs with diabetes are prone to.
• A check of your pet’s pancreas through blood tests and/or abdominal ultrasound, if pancreatitis (inflammation of the pancreas) is suspected as an underlying cause.

Dog diabetes treatment: What you need to know

The mainstay of diabetes treatment in dogs is usually insulin therapy, where prescription insulin doses are regularly administered to supplement the natural insulin they’re lacking, so that they can start to utilise glucose normally again. This most commonly requires twice daily insulin injections, i.e. an injection every 12 hours, administered with a very fine needle or insulin “pen” under your pet’s skin (subcutaneously) immediately after they’ve eaten. Don’t worry - your veterinary team can teach you how to do this so that there is little to no discomfort for your dog and minimal stress for you!

Your pet’s insulin requirements may change over time depending on their diet, their level of activity, and any other health conditions they develop. Therefore, recently diagnosed diabetic dogs are usually started on a “standard” lower-end insulin dose, which may then be adjusted intermittently based on your veterinarian’s regular reassessments of your dog’s blood glucose levels, and their diabetic symptoms and general condition. The overall goal is to have your dog maintaining a healthy body weight, with a normalised appetite, energy, drinking levels and urination levels.

Prescription insulin plus the required monitoring can be financially taxing for owners. The 2025 Pet Health Monitor report indicates that diabetes treatment can add up to around $682 to $1260 per year. If your pet is diagnosed with diabetes, it’s an emotionally-confronting but important step to consider upfront whether you can manage this expense long-term, not to mention the time commitments involved too.

It's very important for your pet’s safety and wellness that they are dosed correctly (i.e. the right amount of insulin, with an appropriate amount of food, given at the correct time interval). Your veterinarian can provide you with some practical tips on this, including troubleshooting common issues such as:

• What to do if you miss a dose of insulin
• What to do if your pet’s not eating

If in doubt, always consult your veterinary team!

Diet and nutrition for diabetic dogs

Traditionally, it has been recommended that diabetic dogs should be fed a prescription diet that is higher in complex carbohydrates (>50% dry matter) and fibre (>10% dry matter), and low in fat. The reasoning for this was that higher levels of fibre within the food will slow glucose absorption into your pet’s bloodstream, helping to reduce big blood sugar “spikes”.

However, more recent studies tend to indicate that it is generally more important to focus on dietary consistency for your dog, i.e. keeping their food type and overall daily quantities stable, and administering their food and associated insulin injections every 12 hours as consistently as possible (with 50% of their daily food portion being given with their morning injection, and 50% with their nightly injection).

Dogs that are underweight or at their ideal weight will often benefit most from a regular balanced diet containing high quality protein and a moderate complex carbohydrate and fibre content. However, overweight pets or those with a history of pancreatitis (inflammation of the pancreas) or hypertriglyceridaemia (excessive fat in their blood) may still require a prescription fat-restricted diet.

And the big question (for your dog at least!): what about treats? It’s best to keep the vast majority of a diabetic dog’s daily food intake within their measured morning and nightly meals, as this will help ensure the best diabetic control for them. However, it’s OK to offer your pet a couple of treats during or after their insulin injection, to help maintain positive associations. Ideally, these should be healthy foods (thumbnail sized pieces of cooked skinless chicken breast, dried chicken breast, dried liver treat, or carrot), rather than a more processed treat with added sugar.

Your vet can help to make personalised recommendations on the best diet for your pet.

Related: What’s the best food for my dog?

Monitoring your diabetic dog

To help keep diabetic pets feeling their best, regular monitoring is essential. The most thorough monitoring will involve regular veterinary check-ins plus you keeping a vigilant eye on your dog at home too!

Related: Why pet insurance matters: Protect your pet and your budget

Monitoring in the veterinary hospital

When your dog is being started on insulin therapy, they may need to stay in a veterinary hospital for several days so that their blood glucose levels can be closely monitored to prevent dangerous hypoglycaemia (low blood sugar), and any associated diabetic unwellness can be treated. However, some generally “healthy” dogs with newly diagnosed diabetes may be able to be managed as outpatients early on too.

Once your dog is settled back in at home again (hooray!), they will usually require veterinary reassessments at least every 1-2 weeks while their condition is being stabilised, and then every 3-6 months thereafter (or any time their condition changes). Depending on your pet’s progress, these reassessments may involve combinations of the following:

1. An assessment of your dog’s blood glucose trends
2. General blood tests to check your dog’s organ function
3. Urine tests to screen your dog for urinary tract infections

Your dog’s blood glucose levels can be measured in two ways:

Using a blood glucose monitor

A drop of blood is collected from your four-legged friend (using a fine syringe or lancet) and applied onto a sample wick loaded into the monitor device, which provides an immediate glucose level reading. A series of these measurements can be performed every 2 hours over the course of a day, which is known as a “blood glucose curve”. This can be done in the veterinary hospital, or owners can be taught how to perform measurements at home.

Using a continuous glucose monitoring device

The small adhesive device is applied onto your pet’s skin, where it continuously reads their glucose levels and sends the data to your phone over several days until it naturally falls off. This can be done at home, and the readings sent to your vet for assessment.

Monitoring your pet at home

Just as important as their regular veterinary checks is you monitoring your pet’s behaviour and activities at home on a day-to-day basis. Often, a vigilant owner will be able to pick up on symptoms that suggest their diabetic dog may need an insulin dose reassessment or general check-up.

It’s a good idea to let your vet know if you notice any of the following symptoms in your diabetic doggo:

• An increase in appetite
• An increase in thirst
• Changes in urination
• Weight loss
• Reduced activity
• Any other symptoms of unwellness, such as vomiting or diarrhoea

Additionally, it’s vital that all diabetic pet owners are familiar with the symptoms of hypoglycaemia (low blood sugar) in their pet, as this requires prompt treatment. More on this below.

Hypoglycaemia in dogs: recognising and managing low blood sugar

Hypoglycaemia is when a pet’s blood glucose drops too low, which can starve their vital organs of energy.

Fasted blood glucose levels in healthy dogs normally range from about 4.4-6.6mmol/L. However, daily blood glucose target ranges for diabetic dogs are higher than this, usually aiming for a lowest glucose reading of around 4.5-8.3mmol/L and a highest reading of 11-14mmol/L.

Blood glucose levels less than 3.3mmol/L can make your pet feel very unwell, while levels below 2.2mmol/L can even be life-threatening.

Hypoglycaemia can occur if your pet receives too much insulin. Common reasons for this to occur are:

• If your pet is accidentally double dosed with insulin (e.g. an insulin dose is given twice due to a communication slip-up between owners).
• If an incorrect syringe is used for your pet’s type of insulin.
• If your pet is given their full insulin dose but then doesn’t eat.
• If your pet’s insulin requirements change over time.

Early symptoms of hypoglycaemia can include:

• Reduced activity or responsiveness
• Confusion
• Wobbliness or weakness
• Muscle tremors

If you see your pet showing any of these symptoms, it’s safest to offer them some food, and then phone your vet for further advice.

As hypoglycaemia worsens, pets can seizure or lose consciousness. This necessitates emergency veterinary treatment (usually an intravenous injection of glucose). Before jumping in the car with your pet, it’s recommended to rub some honey or glucose syrup onto their gums for a little sugar boost.

Complications of diabetes in dogs

Due to their abnormal glucose metabolism, diabetic dogs are unfortunately prone to a few secondary health issues. These include:

• Cataracts: This is when the normally clear lenses within the eyes become cloudy and opaque, which leads to eventual blindness. In some cases, vision can be restored through surgical treatment by a specialist veterinary ophthalmologist, although this is not financially possible for all owners. Cataracts can also trigger inflammation within the eye known as uveitis, which causes sudden eye discomfort, weepiness or redness. This should be treated promptly to relieve pain and help prevent further eye damage.
• Urinary tract infections: These may cause symptoms of general unwellness (e.g. lethargy), more frequent urination, and cloudy, bloody or smelly urine. These should be treated promptly to prevent them progressing to serious kidney infections.

Living with a diabetic dog: Lifestyle adjustments

After they become comfortable with the physical process of administering insulin injections to their dog, most pet-parents find that the biggest long-term lifestyle adjustment is ensuring that someone will be present every 12 hours to administer the pet’s insulin and associated meal. This is something that owners who live by themselves can sometimes find challenging to juggle around regular working hours or social activities.

Dogs with diabetes can still go into boarding, provided that the boarding facility has a staff member who is comfortable administering the pet’s insulin injections. It’s best for diabetic pets to be sent with their regular diet, so that their daily food intake remains consistent, with clear associated feeding and insulin dose instructions. It’s also safest for owners to give carers instructions on the dog’s average daily exercise routines, as sudden significant increases in activity can lower blood sugar and predispose diabetic pets to hypoglycaemic episodes.

Lastly, your dog will still be able to undergo sedation or anaesthesia for planned medical procedures when required, but they will need a reduced insulin dose on the morning of the procedure given they will be fasted from the night prior. Your vet can provide you with personalised advice on how to safely do this for your pet.

Prognosis: Can diabetic dogs live normal lives?

The sweet news is that, with a regular management schedule, proactive monitoring and timely veterinary treatment when required, diabetic dogs can still experience great quality of life and will generally not have their lifespan shortened by their condition. Hooray!

If your dog has been diagnosed with diabetes, remember – it doesn’t mean they can’t live a happy, healthy life. Having Buddy Pet Insurance means you can be covered for the unexpected vet bills that can come with managing diabetes. It’s just one more way we’ve got your back while you focus on helping your furry mate feel their best.

10 Dec 2025