The Canine Ledger

Diabetes in Dogs: Insulin, Home Monitoring, and Glucose Sensors

Diabetes in dogs is lifelong but manageable. The signs, the two emergencies every owner should know, and what the studies say about wearable glucose sensors.

Written by thecanineledger

If your diabetic dog is weak, wobbly, trembling, having a seizure or collapses, especially after an insulin injection: phone your vet immediately. This can be dangerously low blood sugar. If your diabetic dog is lethargic, off food, vomiting or breathing oddly: see a vet today. This can be diabetic ketoacidosis, a medical emergency.

Wearable glucose sensors designed for people are now used to monitor diabetic dogs at home. A 2026 study put one on 23 healthy dogs that did not have diabetes. Of the 19 dogs analysed, 14 recorded at least one low reading, and the authors say the results provide “a context for interpreting FGMS results in diabetic dogs” (Brisman et al., Journal of Veterinary Internal Medicine 2026). FGMS stands for flash glucose monitoring system.

In other words, a low reading on a sensor doesn’t always mean a low blood sugar.

While sensors have made home monitoring far easier, the numbers still need a vet to interpret them. This page sets out what diabetes in dogs involves, the two emergencies to know, and what the sensor studies show.

1. What diabetes is, and which dogs get it

The Merck Veterinary Manual’s owner page defines diabetes as “a chronic disorder of carbohydrate metabolism caused by either a deficiency of insulin or a resistance to insulin” (Merck, Disorders of the Pancreas in Dogs).

Who. “Middle-aged dogs are affected most commonly, with females affected twice as often as males.” Merck names “Miniature Poodles, Dachshunds, Schnauzers, Cairn Terriers, and Beagles” among breeds that seem more prone, “but any breed can be affected.”

Why. Usually, the insulin-producing cells are destroyed “either by the immune system or severe, recurrent inflammation of the pancreas (pancreatitis).” Cushing’s disease, obesity and some long-term drug treatments raise the risk. In unspayed females, the hormones of pregnancy and the heat cycle “can lead to high blood sugar and insulin resistance.”

→ Pancreatitis and the Low-Fat Diet Question · → When to Spay or Neuter: What the Breed Studies Show, and What They Don’t

2. The signs

Merck: “Diabetes can often develop gradually, and the signs may not be noticed at first. Common signs include increased thirst and urination, along with increased appetite and weight loss.”

It also notes that “Cataracts develop often in dogs with poorly controlled diabetes mellitus.” Infections that keep coming back are common.

A dog who is drinking and peeing much more than usual should see a vet. Diabetes is one of several causes.

→ Is It Old Age, or Something Treatable? A Guide to Your Senior Dog

3. Treatment: lifelong, and shared with you

Merck: “Your understanding of the disease and daily care of your pet are critical to successfully managing diabetes. Treatment involves a combination of weight loss, diet, insulin injections, and possibly oral medications.”

Your vet sets the plan. Merck: “Your veterinarian will determine the amount and timing of your pet’s meals, and the dosage and timing of insulin injections. Follow these recommendations very closely.”

Spaying. For unspayed females, Merck says “your dog should be spayed if she is not already.”

Never adjust insulin yourself. Merck: “Do not make changes in the amount or timing of insulin treatments or diet without consulting your veterinarian.” Too much insulin “can result in life-threatening low blood sugar (hypoglycemia)”.

Our note: Insulin products are not interchangeable. Don’t swap your dog’s insulin for another without your vet.

4. The two emergencies

Low blood sugar. Merck: “Signs of dangerously low blood sugar include weakness, lack of coordination, seizures, and collapse. If these signs are seen after administering insulin, call your veterinarian immediately.” Your vet may tell you how to raise your dog’s blood sugar on the way in.

Diabetic ketoacidosis (DKA). Untreated or poorly controlled diabetes can lead to DKA. Merck: “This is a medical emergency that requires immediate treatment and hospitalization to correct. Signs of ketoacidosis include increased thirst and urination, lethargy, weakness, decreased appetite, and trouble breathing.”

Our note: We added vomiting as a warning sign, though Merck’s owner page doesn’t list it. If your dog won’t eat at injection time, follow your vet’s instructions.

→ Emergency Signs in Dogs: When to Go Now, Not Tomorrow

5. Home monitoring and glucose sensors

Merck notes that “Blood glucose measurements are necessary to ensure that the disease is being controlled. Your veterinarian may recommend that you perform this monitoring at home to get the most reliable results.”

What the sensors are. Flash glucose monitoring systems were designed for people. A small sensor sits on the skin and measures glucose in the fluid under it, not in the blood.

How accurate are they in dogs? A 2020 study tested one in 14 dogs with diabetic ketoacidosis. It did not meet the international standard for analytical accuracy, but the authors concluded that “the FGMS provides clinically accurate estimates of BG in dogs with DKA” (Malerba et al., Journal of Veterinary Internal Medicine 2020). BG means blood glucose.

Low readings in healthy dogs. The 2026 study noted that the sensor “might underestimate glucose concentrations during hypoglycemia”. In healthy dogs, 14 of 19 analysed recorded at least one low reading. Low readings were more frequent in smaller dogs.

What this means for you. A sensor gives far more readings than finger-prick tests, which can help your vet. But a single low reading in a dog who seems well may not be real. A low reading in a dog who is weak or wobbly is an emergency, whatever the sensor shows.

Our note: The “what this means for you” paragraph is ours. If you think your dog’s blood sugar is low, phone your vet rather than wait for a second test.

Our note: The main North American guidelines are free to read on the AAHA website, and we have now read them (Behrend et al., Journal of the American Animal Hospital Association 2018, updated 2022). They say sensors “appear to be generally accurate”, but that variation “in patients with low glucose readings may be more common and more clinically significant”. They recommend checking a low sensor reading with a blood glucose meter, “particularly when clinical signs of hypoglycemia are not evident”. The guidelines were sponsored by a grant from two animal health companies.

6. What we could not verify

Commonly saidWhat we found
“Diabetic dogs can’t live a normal life”We found no outcome study we could read. Merck describes it as manageable with daily care.
“A sensor is as good as a blood test”Not quite. It didn’t meet the analytical standard in dogs with DKA, though it was judged clinically accurate.
“A low sensor reading always means a hypo”Not always. Healthy dogs without diabetes recorded low readings in a 2026 study.
“Diabetes in dogs can go into remission”Not usually. The AAHA guidelines discuss remission in cats. In dogs, they say the loss of insulin-making cells “tends to be rapid and progressive”, though unspayed females “may be transiently or permanently diabetic” because of heat-cycle hormones. Ask your vet.
“If my dog seems fine, I can adjust the dose”No. Merck says never change insulin or diet without your vet.

Sources

Always confirm with your vet before acting on anything on this page.