Dogs

Diabetes mellitus in dogs – everything you need to know (from symptoms to treatment)

Diabetes mellitus in dogs is a common endocrine disease, where the body isn’t able to efficiently regulate blood sugar levels and metabolism. It’s a complex chronic disease that requires careful management, constant monitoring, and life-long therapy. 

Most cases occur in middle-aged or older dogs, with females being twice as often affected as males. There also seems to be a certain breed predisposition (the incidence appears higher in Schnauzers, Poodles, Dachshunds…) but any breed can be affected.

Sadly, it seems that the number of cases is continually increasing year by year 😟 This may be due to several factors such as an increase in obesity in dogs or their longer life span. 

What causes diabetes mellitus in dogs?

Most people know that diabetes has something to do with insulin and blood sugar. So why is diabetes such a big problem?

Because human bodies, as well as animal bodies, run on glucose. It’s the source of energy for our cells, the fuel for our bodies.

Our cells need to be able to process glucose, otherwise, they cannot function.

This is where insulin comes into play. Insulin is a hormone that regulates glucose levels in the blood and its absorption into cells. 

What is pancreas and why is it important?

The pancreas is a vital organ on the right side of the abdomen. It’s technically a gland with exocrine and endocrine functions.

As an endocrine gland, it produces hormones insulin and glucagon, which are responsible for regulating the glucose level in the blood.

As an exocrine gland, it produces enzymes that aid digestion in the small intestine.

Thanks to this duality, we see different diseases, depending on which part of the pancreas is affected. Problems in the endocrine function can result in diabetes mellitus. Problems in the exocrine part can lead to pancreatitis – the inflammation of the pancreas

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The role of insulin:

So insulin is a hormone that is produced in the pancreas. It regulates the sugar blood levels and glucose resorption in cells. In other words, it “tells” the cells to grab glucose from the blood and use it as an energy source. 


In the case of diabetes, the cells cannot absorb glucose from the blood and use it as an energy source.

Since the cells are not absorbing glucose from the blood, it builds up in the bloodstream and that is why we can measure elevated blood sugar levels. The cells don’t have enough glucose even when they need it and there’s too much in the blood. 

There are 2 types of diabetes in dogs:

  • Insulin-deficiency diabetes: this is the most common type of diabetes in dogs. It happens when the pancreas isn’t producing enough insulin. It can be absolute (no insulin is produced) or relative (not enough insulin is produced).
  • Insulin-resistance diabetes: it happens when the cells stop responding to insulin. It means that enough insulin is produced in the pancreas, but the cells are not absorbing glucose from the blood. This is a rare form of diabetes in dogs. 

Risk factors for diabetes in dogs

Diabetes usually occurs in older dogs. Female dogs have a higher occurrence than males.

There are a few breeds that can be predisposed to diabetes mellitus, but the truth is any dog of any breed can develop the disease. 

Obesity is a proven risk factor for insulin-resistant diabetes in dogs.

Pancreatitis and some other diseases can also lead to diabetes. 

Female dogs produce the hormone progesterone during diestrus and pregnancy, which can sometimes lead to insulin resistance. 

Risk factors for diabetes mellitus in dogs:

  • Age – older dogs have a higher occurrence than younger dogs
  • Sex – female dogs have a higher occurrence than male dogs
  • Genetics – some breeds are predisposed to diabetes, but any dog can develop the disease
  • Obesity
  • Pancreatitis
  • Other health conditions – Cushing disease, some autoimmune disorders, viral diseases…
  • Long-term use of corticosteroids
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What are the symptoms of diabetes in dogs?

Diabetes in dogs often develops gradually, so owners often don’t recognize the signs at the beginning. 

In the case of uncomplicated diabetes, the usual symptoms are increased thirst and urination, and increased appetite but at the same time weight loss

The body is trying to “feed” the cells, which are starved for glucose.

However, the cells cannot absorb the energy they so desperately need. So the body starts to break down its fat and protein reserves as an alternative energy source. That explains hunger and weight loss at the same time. 

In medicine, you can say that too much of anything is poison. Even too much of the “good” and necessary stuff. Too much glucose in the blood is damaging to the organs, especially the kidneys, heart, eyes, blood vessels, or nerves. 

Sometimes the dog is suffering from an inflammation of the whole pancreas, which is actually causing diabetes. In this case, we can see also signs associated with pancreatitis such as abdominal pain.

A common complication of diabetes in dogs is lower resistance to bacterial and fungal infections, often resulting in persistent urinary tract infections, bronchopneumonia, dermatitis, or prostatitis.

Cataracts (opacities in the lens of the eye) are often associated with poorly managed diabetes in dogs. 

Initial symptoms of diabetes mellitus in dogs:

  • Increased thirst
  • Increased urination
  • Increased appetite
  • Weight loss
  • Muscle mass loss
  • (signs of pancreatitis)

Signs of more advanced diabetes in dogs include

  • Loss of appetite
  • Lack of energy, weakness, and later lethargy
  • Vomiting

Uncontrolled diabetes in dogs leads to organ damage and can cause:

  • Cataracts 
  • Recurrent or persistent urinary tract infections (most common, but other infections are possible as well)
  • Damage to the kidneys resulting in kidney failure
  • Enlarged liver
  • Seizures
  • Diabetic ketoacidosis

Diabetic ketoacidosis

A dangerous form of decompensated diabetes mellitus is diabetic ketoacidosis.

❗️It’s a potentially life-threatening condition that requires rapid medical intervention❗️

Your dog might display signs like rapid breathing, lethargy, vomiting, and/or sweet-smelling breath


If you are an owner of a diabetic dog, you should have ketone testing sticks with you all the time. If your dog is displaying any of the above-mentioned symptoms, test his urine for ketones. If the ketone test is positive, call your vet immediately. 

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Diagnosis of diabetes in dogs

Diabetes in dogs results in high blood sugar levels (hyperglycemia) and glucose in urine (glycosuria), even when the dog is fasting. Both glucose in the blood, as well as glucose in the urine, can be measured with simple tests. 


Sometimes other tests and diagnostic tools are needed to assess the damage to different organs. 

Treatment of diabetes in dogs

Diabetes cannot be cured, but it can be successfully managed. However, the treatment requires more than just insulin injections. 

Successful management of the disease depends on 2 key factors:

  • excellent communication between the vet and the owner
  • full cooperation of the owner

If this doesn’t work, the treatment won’t work, sorry… 🤷‍♀️

If the owner doesn’t fully cooperate, the dog will never be stable. If the communication between the vet and the owner doesn’t work, the owner won’t fully understand what’s going on (and again, will not cooperate…).

If you don’t trust your vet for whatever reason, or if your vet doesn’t have good communication skills (yeah, I know this happens), find a different vet you can trust.

diabetes mellitus in dogs

A dog with diabetes needs 4 things to have a happy life:

  • daily insulin injections
  • dietary management and individual nutrition plan
  • frequent and regular monitoring (by both the owner and the vet)
  • exercise to maintain his weight

🔻 Insulin 🔻

A dog with diabetes mellitus needs 2 insulin injections each day. The shots go under the skin.

I know it a lot of owners have a problem with it at first, but believe me, once you get over the trembling hands’ phase, it’s not so hard ❤️

🔻 Nutrition 🔻

Another important component of disease management is nutrition. 


You will need a whole dietary management plan. It’s not just what should you feed your dog, but also how often, how much, and how long should you wait after the insulin injection…

It needs to be tailored to your dog’s needs. If your dog is obese, he needs to lose weight safely. If he’s underweight, he needs to gain weight safely.

There are guidelines on proper feeding times depending on the time of insulin administration. There are guidelines on how much fiber, protein or carbohydrates should a dog with diabetes get. 

Your vet might prescribe a special veterinary diet designed for dogs with diabetes (for example Royal Canin Diabetic or Hill’s Diabetes Care).

The best thing you can do is to sit down with your vet and let him create an individual feeding plan specially tailored to your pup’s needs. 

🔻 Monitoring 🔻

Frequent monitoring is another key element of the treatment of diabetes in dogs.

Depending on the results, the insulin dosage might change, your whole nutrition plan might change, even your monitoring frequency might change… and when you think the dog is finally stable it will probably change again at some point 🤦‍♀️ 🤷‍♀️

This doesn’t mean that the changes have to be bad, it just means you need to be aware of them and adapt your therapy plan accordingly.

So be prepared for frequent visits to the veterinary clinic at the beginning for medication adjustments.

Glucometers (devices that measure blood glucose levels) and urine strips (for monitoring glucose and ketone levels in urine) are effective tools that will help you monitor your pup at home. 

🔻 Excercise 🔻

Keep your pup active. It will help him not just physically, but also mentally 😊

And it’s a nice way of spending time together ☺️

Do you see why I said that communication with your vet and your cooperation are the most important things for the successful management of this complicated disease? Because they are. And I say it again, without communication between you and your vet and your full cooperation the treatment won’t work. 

diabetes in dogs

How long do dogs live with diabetes?

Diabetes in dogs cannot be cured, but it can be managed successfully. In most cases, this depends on you, the owner.

If your pup’s diabetes is regulated, and the treatment and monitoring are frequent and consistent, the prognosis for your pup is good. 

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Diabetes in dogs is a disease that requires life-long treatment and consistent monitoring. However, without the full cooperation of the owner, it’s impossible to treat it successfully. The key is excellent communication between the vet and the owner, and the owner’s compliance.

You need to do what the vet tells you to do. It’s as simple as that. You need to trust your vet. Otherwise, it just won’t work and your pup will be the one who will pay for it with his health and potentially his life. 

If diabetes is regulated and monitored, there is no reason why your pup shouldn’t have a long and happy life. Trust your vet, trust yourself and trust the process.

It will be ok, I promise, you got this ❤️ ☺️

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While I am a veterinarian, this article is not intended to replace professional veterinary advice. If you have any medical concerns about your pet, consult your vet immediately. Always seek professional assistance if you are unsure of your pet’s health.


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