Diabetes in Dogs

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Diabetes in Dogs

If your dog has recently been diagnosed with diabetes, you may be feeling scared and overwhelmed. Diabetes seems like a complicated disease, but with early detection and management, your dog may be able to lead a full, happy life. Continue reading to learn more about diabetes in dogs, including causes, signs, and treatment.

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What is Diabetes?

Diabetes Mellitus is a disease that occurs when the pancreas has trouble producing insulin. Insulin is a hormone that helps cells absorb glucose (sugars) to fuel tissues and organs. Without insulin, a diabetic dog can eat food all day long and have tons of glucose trapped in their bloodstream, but they can’t use any of it! So, just like people, a diabetic dog needs insulin injections twice a day so they can use the glucose they consume.

Usually, the kidneys help control glucose. However, diabetes causes the kidneys to become overwhelmed by the amount of sugar in the bloodstream, allowing the excess sugar to spill into the urine. Water follows the glucose and causes diabetic animals to urinate more than usual. Since this causes dehydration, animals then seek out more water and drink more than usual. It’s also common for diabetic animals to develop urinary tract infections, since the glucose in the urine is an energy source for bacteria.

In the long run, without insulin injections (treatment), a dog will start breaking down its own body muscle to try to access glucose. The products of this process (ketones) are toxic to the body and can be fatal (diabetic ketoacidosis).

Causes of Diabetes in Dogs

In the pancreas, there is a cell type called Beta cells that produces insulin. In some dogs, there aren’t enough of these cells, or they aren’t producing enough insulin, or both. This is similar to Type II diabetes in people, ie. adult-onset, or “non-insulin-dependent” diabetes. In some cases, no insulin is being produced at all. This is similar to Type I diabetes in people, ie. juvenile-onset, or “insulin-dependent” diabetes. Unfortunately, dogs most often have Type I diabetes and once diagnosed, will need insulin injections for life.

Type I vs. Type II Diabetes

Like in humans, there are two main types of diabetes mellitus in dogs. However, the specific mechanism of each type in dogs differs from how the disease develops in humans.

Type 1 Diabetes mellitus is the most common type of diabetes reported in dogs. It is described as the absolute deficiency of insulin in the system due to the destruction of insulin-producing cells in the pancreas. The underlying cause is usually immune-mediated or pancreatitis (severe inflammation of the pancreas), but spontaneous destruction has also been reported.

Type 2 Diabetes is also known as “insulin-resistant” diabetes. It is characterized by the cell’s inability to respond to the insulin produced by the pancreas, leading to a deficiency of uptake of glucose from the blood into cells and tissues. This is often a secondary complication to a primary disease, usually another hormonal disorder such as Cushing’s disease.

Signs of Diabetes in Dogs

The most common signs of diabetes are increased thirst, urination, and hunger. A pet may also experience weight loss and lethargy. Often diabetic animals start out as overweight and end up losing muscle mass, sometimes to the point of looking emaciated. This commonly occurs if the dog isn’t diagnosed and treated in a timely fashion. Fortunately, many, if not all, of these signs can resolve with treatment.

Less common signs associated with the disease are weakness, recurrent infections, development of cataracts, poor coat quality, and seizures, which happens when the dog’s blood glucose level drop to dangerous levels.

Diagnosing Diabetes in Dogs

Diabetes Mellitus is diagnosed by having a repeatedly high glucose level in the bloodstream, glucose present in the urine, and other changes in bloodwork, combined with the clinical signs mentioned above. If you suspect your dog has diabetes, it’s important to have them diagnosed and begin treatment as soon as possible.

Treatment of Diabetes in Dogs


Insulin injections are typically given twice daily (every 12 hours), 30 minutes to 1 hour after a meal. Insulin doses are initially calculated by your vet. Then, based on your dog’s response, the dose may be adjusted over the course of several weeks or months. Some dogs become regulated on insulin quite quickly, and others need some fine-tuning.

It’s important to be patient when first starting insulin therapy for your dog. Never adjust any doses without consulting your vet. Many dogs need to be on a newly calculated dose for 2-3 weeks before their response can be evaluated and adjusted.

There are different types of insulin, and your vet will choose the appropriate type for your dog. Part of treatment is continuing to monitor your dog’s response to insulin over time. Your vet may periodically ask you to drop your dog off for the day so that your dog’s glucose can be checked every 2 hours or so. This day-long test is called a Blood Glucose Curve. It helps show your dog’s response to insulin therapy throughout a typical day.

Your vet can explain and demonstrate to you how to store, handle, and administer insulin injections. The needles are very small, and surprisingly, most dogs tolerate injections quite well.


Controlling your diabetic dog’s diet is very important! Consult with your vet about prescription and over-the-counter options to feed your diabetic dog.

How to Prevent Your Dog from Developing Diabetes

Unfortunately, it’s impossible to prevent Type I Diabetes Mellitus, which is the most common type in dogs. Often, a pet may have an auto-immune disease which causes them to destroy their own Beta cells. This prevents them from producing any insulin at all, making them “insulin-dependent” for life.

When should you contact a vet?

If your dog has increased thirst, urination, hunger, or has had these signs for a while and is now losing weight, or is lethargic, dehydrated, and has a poor haircoat, your vet will need to run bloodwork or other lab tests to help diagnose the cause. Many diseases cause these types of signs, and your vet will need to know what’s going on in order to treat your dog properly.

Read more:

My dog has Cushing’s disease. What does this mean?

Is my dog hypothyroid?

Kidney Failure in Dogs

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