Diabetes in Dogs

Has your dog’s diagnosis of ‘diabetes’ left you concerned and confused?

To an owner, the responsibility of balancing their best buddy’s blood glucose feels as nerve-wracking as crossing over a ravine with your eyes closed. But the good news is there’s no need to worry because guidance is available and the bridge has handrails to keep you on track.

Diabetes Mellitus in Dogs (sugar diabetes) is common. Normally, blood sugar levels are controlled by a hormone called insulin. Diabetic dogs lack sufficient insulin to keep sugar levels steady, which results in high blood glucose. Clues that this is the case include a thirsty dog that eats well but loses weight.

Dogs at Risk of Diabetes

Why do some dogs develop diabetes but not others?

Take two dogs from the same litter. One goes on to develop diabetes but the other doesn’t. Why is this?

Like dodging a bullet, some dogs are lucky because events turn in their favour. Factors such as diet, weight, exercise levels, medications, and dog desexing all have a part to play. Some of these an owner can control, whilst others (such as breed) are a done deal.

Let’s look at these influencing factors.

Risk Factor 1: Breed

Dog breeds inherent characteristics that make them instantly recognisable, for example, for a dachshund it’s that long back and little legs. But Dachshunds don’t just share sausage-dog looks; they inherit genes which make diabetes more likely. Other ‘at risk’ breeds include [£]:

  • Dachshunds
  • Miniature Schnauzers
  • Poodle
  • Bichon Frise
  • Samoyed
  • Cairn Terriers
  • Beagles
  • Pugs
breeds prone for diabetes

Risk  Factor 2: Female Dogs

A female dog coming into heat produces large surges of reproductive hormones. These hormones block the action of insulin and stop it working. For a female dog in oestrus, this blocking action of makes the difference between remaining healthy or tipping over into diabetes.

Indeed, for newly diagnosed females, if they are entire, the vet will suggest neutering to make their condition easier to manage.

Risk Factor 3: Overweight Fur-friends

There’s a link between obesity and diabetes in dogs. How does fat affect doggy diabetes?

Carrying too much fat encourages the body to produce a range of natural chemicals and hormones, such as adiponectin, acute phase proteins, and pro-inflammatory cytokines. These substances interfere with the action of insulin and make it less effective. (Sounds familiar? The effect is similar to those of reproductive hormones.)

Risk Factor 4: Medications

Some medications are known to worsen diabetes. Corticosteroids, such as prednisolone, along with progesterone and certain diuretics, are best avoided in diabetic animals.

Risk Factor 5: Other Health Conditions

Chicken or egg?

Some health problems mean the body struggles to maintain a natural balance, including control of blood sugar levels. . Treat that underlying problem and it helps stabilise or even prevent diabetes. Examples include:

  • Hypothyroidism: Under production of thyroid hormone affects the uptake of insulin
  • Cushing’s disease: Glands overproduce natural steroid hormone, which antagonizes insulin.
  • Acromegaly: Too much growth hormone blocks the action of insulin
  • Pancreatitis: An inflamed pancreas struggles to produce insulin
  • Infection: Any source of infection makes it harder for insulin to work. This can also be a chicken and egg situation since diabetes makes urine infections more likely.

Add together enough risk factors and this ramps up the chances of a dog becoming diabetic. So over-feeding an entire female dachshund is akin to inviting the dog to become diabetic. Whilst spaying that female and keeping her slim helps keep her healthy.

What causes diabetes in Dogs?

The cause of diabetes in dogs is a lack of natural insulin production.

The action of insulin is to allow glucose into cells and provide energy for metabolism. A lack of insulin and not enough sugar soaks into those cells, leaving it sloshing around in the bloodstream.

Think of this like a see-saw. On one end is sugar and the other is insulin. When the amounts are correct, blood glucose levels remain steady and the cells are nourished. However, when there’s not enough insulin, this allows the glucose levels to rise and the cells are starved of energy.

what causes diabetes in dogs

An Aside about Type 1 vs Type 2 Diabetes

Human diabetes is categorised into two types: These are

  • Type 1 diabetes: The pancreas can’t produce sufficient insulin
  • Type 2 diabetes: The body’s cells don’t register the presence of insulin

In dogs, things aren’t so clear cut. Most dogs suffer Type 1 diabetes and a lack of insulin production and experts tell us that Type 2 diabetes is rare in dogs (the opposite is true in cats!)

Symptoms of Diabetes in Dogs

It’s the raised levels of glucose in the blood that cause the symptoms of diabetes. The sugar sucks fluid out of the cells and into the bloodstream. Not only this but above a certain threshold the kidneys can’t recycle the sugar and so glucose leaks out in the urine.  This means the body is constantly seeking replacement fluid, which we see as a thirsty dog that pees constantly. With lots of calories lost in the urine the dog is hungry and eats well, but still loses weight.

The classic signs of diabetes in dogs include:

  • Drinking a lot
  • Urinary accidents
  • Urinating for a long time
  • Weight loss
  • Lack of energy
  • A dull coat

Untreated diabetes in dogs may develop complications such as:

  • Cataracts
  • Cystitis
  • Vomiting
  • Breath that smells of acetone
  • Collapse

Diagnosing Diabetes

If you think your dog may have diabetes, visit the vet and take a urine sample along. The vet can run a simple dipstick test for glucose. If there’s no glucose in the urine, then diabetes is unlikely. However, if glucose is present,  other tests are required to pin down the diagnosis (health issues other than diabetes can lead to sugar in urine.)

The tests most commonly run are:

  • A screening blood profile: This provides information about organ function along with red and white blood cell health. This is to check for other conditions that cause increased thirst, such as kidney disease.
  • Blood fructosamine test: This test gives an overview of the blood sugar levels for the past two to three weeks, and is useful for monitoring purposes.
  • Urine culture: That sugary urine is an ideal food for bacteria, so urinary tract infections are common.

The vet may also screen the pet for health problems which aggravate diabetes, such as Cushing’s disease or underactive thyroid glands.

Treatment for Diabetes

Successful treatment means insulin injection, a good diet, encouraging weight loss, and treating any underlying health concerns.


Our doggy diabetics usually stabilise on twice-daily insulin injections. If the thought of injecting your fur-friend makes you uneasy…there’s no need to be. The needle is hair thin and a tasty treat afterwards soon has the dog eager to take part.

All About Insulin

Insulin is a liquid that is injected into the dog. Specific veterinary insulins are available, and the vet will prescribe these ahead of insulins used for people.

Storing Insulin

The insulin molecule is long and delicate. It degrades quickly and the bottle of insulin must be treated with care. This means storing it in a cool place (such as the salad drawer of a fridge), never shaking the bottle, and discarding the vial after one month’s use.

Insulin Injections

Traditionally insulin is injected using special syringes with tiny needles. Your vet will teach you how to inject. This isn’t difficult but does need to be done with care. Incorrect injection technique, such as injecting into the fur rather than the skin, is a common cause of poor diabetes control.

However, Caninsulin VetPen is now available which makes this even easier. This handy device looks like a pen and you simply dial in the dose, hold the tip against the pet, and press a button.

A top tip is to vary the size of each insulin injection. It’s handy to develop the habit of alternating between the left and right-hand side, front and back of the scruff. This prevents the skin from toughening up in one spot, which stops full absorption of the glucose.

The Timing of Insulin Injections

It’s important the dog eats before having their insulin dose. This is because there’s a risk of the sugar levels dipping too low if they receive insulin on an empty stomach.

For twice-daily treatment, offer a meal ahead of each injection. If the dog eats, go ahead with that dose. Some regimes are more complex (depending on the insulin type) and involve feeding 6 – 7 hours after the insulin. But your vet will discuss if this is necessary.

But What if the Dog Doesn’t Eat…

If the dog refuses a meal, give a half dose of insulin. This reduces complications, such as ketosis (see later), without risking low blood sugar.

However, if the dog skips more than one meal or they seem unwell, always phone the vet for advice.

Insulin Resistance

Sometimes it’s hard to find the right dose of insulin. The vet may keep adjusting the dose upwards, and yet the dog seems no better. If this is the case, the vet may suspect insulin resistance. As the name suggests, this is when the body is ‘resistant’ to the effects of insulin.

A common reason is the body mounting an immune response to the insulin molecule, which damages it. If this is the case, changing the type of insulin may help.

A Note about Oral Hypoglycaemic Tablets

Sadly, tablets used to control diabetes in people rarely work in dogs. Medications such as Metformin or Glipizide just don’t cut it in canines and are rarely used.


It’s vital to work out the right dose of insulin to give the dog. Get it wrong and long term high sugar levels cause damage whilst very low glucose levels are life-threatening. To find the ideal dose requires ongoing monitoring, some of which is done at home and some at the vet clinic.

Blood Glucose Curves

This involves tracking blood glucose levels during the day. To do this, a pinprick of blood is tested every one to two hours. This can be done at home by a confident owner or else as an in-patient at the clinic.

The results give the vet vital information about:

  • How well the body responds to insulin,
  • when insulin activity reaches its peak, and
  • if a dose adjustment is necessary.

For newly diagnosed dogs a glucose curve may be required every couple of weeks. But for stable dogs, once every 6 – 12 months is sufficient.


This is another way of judging if the insulin dose needs changing. This involves a single blood draw which is analysed for the presence of a sugar called fructosamine. This reflects the average blood sugar level over the past couple of weeks. If the reading is consistently high, then increasing the dose is recommended.

Physical Exams

Check-ups are advisable every three to six months. This allows the vet to spot problems, such as an ear infection or dental disease, which impact on diabetes control. The vet may request a urine sample for culture, to check for low-level infection that lacks symptoms.

Monitoring at Home

A great safety net is to do a daily urine dipstick test using strips that check for ketones (Ketodiastix) A well-managed diabetic is always negative for ketones. The latter are natural toxins, the result of burning fat for energy, and build-up when glucose control is poor.

If ketones are present let the vet know. If the dog is unwell, such as not eating or lethargic, contact the vet immediately. Ketones in the urine are an early warning sign not to be ignored since ketotic dogs can become very sick indeed.

The Highs and Lows of Diabetes

Having a very high or very low blood glucose comes with their own set of problems (Remember that narrow bridge?) It’s important to know what to watch for and what to do if you suspect the dog’s diabetes is unstable.

if untreated diabetes in dogs


This is a toxic condition which occurs when blood glucose remains too high for too long. When deprived of glucose, in the search for usable energy, the cells breakdown fat. This releases a raft of toxic waste products that slowly poison the body. These ‘ketones’ makes the dog feel ill and are dangerous when left unchecked.  Signs to watch for include:

  • Extreme thirst
  • Lack of appetite
  • Vomiting
  • Severe lethargy and drowsiness
  • An acetone smell to the breath
  • Collapse

Ketoacidosis happens when the insulin dose is too low. There are many reasons this can happen, for example:

  • Poor injection technique meaning the dog doesn’t get the full dose
  • The insulin is damaged and therefore doesn’t work
  • Another health problem means the body doesn’t register the insulin properly

If you suspect ketoacidosis, call the vet urgently. Severe cases need hospitalisation for supportive care with intravenous fluids and an insulin infusion.

Low Blood Sugar

On the other side of the narrow bridge is low blood glucose (hypoglycaemia), If untreated,  it can lead to coma and death.

In a diabetic, this is the result of getting too much insulin. A simple example of this is giving insulin but the dog failed to eat. Signs include:

  • Extreme drowsiness
  • Weakness
  • Lack of appetite.

Notice how there’s an overlap with signs of ketoacidosis?

This is one reason why home urine tests are so helpful. It can help spot whether the problem is too much or too little insulin.

  • Absence of glucose in the urine indicates low blood sugar is the problem
  • Ketones in the urine indicate high blood sugar is the cause.

Long story short, low blood glucose is dangerous, so give the dog some honey and call the vet as an emergency.


Human diabetics have to watch what they eat to stop large swings in their blood glucose levels.  The same principle applies to dogs, with the type of food, quantity, and timing of each meal all playing a part. This said, there’s no need to set an overly rigid regime. In an ideal world, everything would be constant, but when you have to work late, pushing a meal back by a couple of hours in unlikely to cause a problem as a one-off.

The Best Food for Diabetic Dogs

The general rules for best control of doggy diabetes include:

meal plan for diabetic dogs
  • Try to keep the type of food consistent. This allows the body to better ‘budget’ for what sugar levels to expect.
  • Feed a good quality diet, avoiding plant-based proteins and cheap fillers. The latter can cause spikes in blood glucose that are hard to control.
  • Give treats sparingly
  • Feed at roughly the same time each day.
  • Keep the dog’s exercise roughly the same so as to keep their energy demands constant)

Your vet may recommend a special diet for your diabetic dogs, such as Hills MD, RD, ID, or CD, or Purina OM, HA, or DM.  These diets provide slow-release energy and avoid spikes in blood glucose.

No one diet is ideal for all diabetic dogs. This should be selected on an individual basis, depending on whether the dog is over or underweight, or has other health conditions (such as kidney disease or lack of pancreatic enzymes).

For example, it’s important an overweight diabetic dog loses weight (in a safe way) which improves diabetes control. This needs a good quality, high fibre, low-calorie diet. Alternatively, a thin dog needs building up, which requires a calorie-dense, slow energy release food.


Some commercial diets are high in humectants which mess up blood glucose control. If you have your heart set on a home-prepared diet then work with a veterinary nutritionist to find the right recipe.

In general, follow the same recommendations as a human diabetic, such as feeding carbohydrates with a low or medium glycaemic index (causes lower spikes in blood glucose). Examples of the latter include fruit and vegetables, whole grains, cooked potato, sweet potato, and brown rice.

Conversely, avoid highly processed carbohydrates, such as white bread, white rice, or products high in glucose. These send blood glucose levels on a roller-coaster ride of highs and lows, which nobody wants.


Protein is digested more slowly than carbohydrate, which is great news for keeping blood glucose steady. Again, a good quality protein such as a slice of named meat is fine for the majority of diabetics. The exception is those dogs with specific health problems such as kidney or liver disease.


Diabetics don’t especially need a low-fat diet, except if the dog is prone to pancreatitis or exocrine pancreatic insufficiency. Indeed, fat is a useful source of calories for underweight dogs and helps build them up.


Fibre is great for diabetics, but don’t go mad. The idea is to slow up gut transit time and keep blood glucose levels steady. But too much of a good thing causes fermentation in the bowel, which speeds glucose absorption (a bad thing) and room-clearing flatulence.

Treats for Diabetic Dogs

Having a diabetic dog doesn’t mean dull treats! Just avoid processed treats high in carbohydrate or containing propylene glycol. Instead offer tempting morsels such as freeze-dried meats (avoid those sourced from Overseas), dehydrated meats, dried salmon or liver, tuna or sardines in spring water, green beans, sugar snap peas, or carrot sticks.

Exercise and Activity for Diabetic Dogs

A diabetic dog should lead a normal life and enjoy their walks. But exercise does burn calories, which means gobbling up blood sugar. The trick is not to overstep the mark and cause dangerously low blood sugar levels.

Try to keep the amount of exercise the same for every day. And if the dog plays hard with their pals in the park, then pack a treat or two in case their blood sugar dips. But don’t wrap your dog up in cotton wool, this simply isn’t necessary.

Natural remedies for diabetes in dogs

Insulin and a good diet are the cornerstones of diabetes management.  There is no natural supplement which will do the job instead. However, some dietary supplements can be beneficial but others not so, so don’t assume that because the supplement is recommended for human diabetics that it’s a good thing for dogs. Here’s the heads up on dietary supplements, what’s OK and what’s not:

Glucosamine: This is a joint supplement commonly given to older arthritic dogs. Although glucosamine is a sugar-derivative, there is no evidence to show it destabilizes diabetics and is thought to be fine for diabetic dogs with stiff joints

Omega 3 Fatty Acids: Fish oil supplements can be beneficial to overall good health and brainpower. However, avoid high doses as this can make glucose control unpredictable. Stick with a moderate dose of less than 300mg per 10kg bodyweight.

Zinc: Although recommended for people, zinc is potentially toxic to dogs. Avoid giving a supplement and stick to the low levels contained in most canine multi-vitamin products.

Managing a Diabetic Dog

The highs and lows of diabetes can make this seem in intimidating condition. However, you’re not in it alone and most dogs do very well indeed on treatment. Be confident that a stabilised diabetic dog will be just as active and happy as before.

However, there will be challenges along the way. Help yourself to help the dog by following the advice in this article. Plus, find a vet you can work with so that if the dog hits a sticky patch, they have your back.

So stop worrying and go get on with things, since there are balls needing to be chased, even though your best buddy is diabetic.