Insulin for Dogs: A First-Choice Treatment for Canine Diabetes

Diabetes is a condition that causes a dog’s blood sugar levels to be too high. High blood sugar causes many problems, including cataracts and compromised immunity. 

Fortunately, diabetes can be treated in most dogs with a combination of diet, exercise, and insulin. Insulin is a medication that lowers blood sugar levels. There are many types of insulin available for dogs.

Below, we’ll discuss what insulin is, how it’s given to dogs, potential side effects, and what to do if you missed a dose.

What is insulin for dogs, and what is it used for?

Insulin is a natural hormone produced by the pancreas after a dog eats a meal. Insulin’s job is to move sugar (glucose) from the bloodstream to the body’s cells, where it is used. This prevents a dog’s blood sugar from becoming too high.

If a dog’s body doesn’t make enough insulin or a dog develops insulin resistance, their cells don’t get enough sugar to function. So the body has to use other energy sources, such as fat and protein, to fuel body functions. This can cause:

• Diabetes

• Weight loss

• Dehydration

• Ketoacidosis, a dangerous diabetes complication 

Dogs with diabetes can be treated with insulin to help replace what their body isn’t able to make or use on its own.

Types of insulin for dogs

There are different types of insulin available for dogs. Only Vetsulin and ProZinc are FDA approved for use in dogs. Veterinarians may also prescribe some human insulin products to dogs off-label.

Insulins can be short acting and last for 12 hours. They can also be long acting and help control your dog’s blood sugar for up to 24 hours. There are also intermediate-acting insulins, which work for 12 to 24 hours.

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Here are the insulin brands that can be prescribed for dogs: 

• Vetsulin (lente)

• ProZinc (protamine zinc)

• Lantus (glargine)

• Novolin N (NPH)

• Humulin N (NPH)

• Levemir (detemir)

What is the dosage of insulin for dogs, and how is it given?

Insulin is given as an injection under the skin once or twice a day, typically after your dog eats a meal.

Most dogs are started on intermediate-acting insulin injections twice daily. But the type of insulin your dog needs will depend on your pup’s situation. What works for one dog may not work for another.

There is usually some trial and error required to figure out what works best for your dog. In addition, not all types of insulin are available everywhere. The cost of insulin can also determine what type to use for your dog.

When you start giving a dog insulin, patience is key. Expect to have several rechecks with your veterinarian to get the dosage right. Once the dosage is right, expect follow-up visits to your vet every 6 months or as needed to control symptoms.

It’s also important to give your dog their insulin as scheduled and the right way to manage their diabetes symptoms.

Tips on how to give insulin to dogs

One of the hardest parts of insulin treatment is that it has to be given via an injection under the skin. Never fear — most dogs don’t notice the poke because the needle is tiny.

If you feel uncertain, ask a vet to show you how to give the injections. Most veterinarians include injection lessons as part of teaching people to care for pets with diabetes.

Below are some additional tips to help you give your dog their insulin.

Use the correct syringe

Different insulins use different types of syringes to accurately measure your dog’s dosage. Insulin syringes are either U-100 or U-40, based on the type of insulin and dosage. 

Using the wrong syringe will result in giving the wrong amount of insulin, which could harm your dog. Verify with a veterinarian what syringes you will need and the correct amount to fill each syringe. Also ask them how to dispose of needles.

Give insulin after your dog eats

Insulin will lower blood sugar, so insulin must be given after a dog has eaten a meal to prevent hypoglycemia. If your dog doesn’t eat, follow the vet’s instructions for this situation. A veterinarian will usually provide guidance on how to give your dog a reduced insulin dose.

Store insulin correctly

Insulin is a fragile medication that needs to be stored out of the heat and away from light. Some insulin can also be ruined by too much agitation. So don’t shake that bottle without first reading the instructions carefully. Store insulin in the fridge. Before use, gently roll or shake the bottle, depending on your instructions.

What should you do if your dog misses a dose of insulin?

If you miss giving your dog a dose of insulin, it is likely not a big deal. But you should call your veterinarian to ask when you should give the next dose of insulin.

If your vet is not available and your dog is acting normal and eating and drinking, skip the missed dose. Then give them the next dose at the regularly scheduled time.

If you miss a dose of insulin, your dog may show some diabetes symptoms, such as peeing and drinking more. But symptoms are usually temporary and clear up as soon as your dog is back on their regular insulin schedule.

Never double up doses to make up for the missed dose. This could result in life-threatening low blood sugar.

What are the side effects and risks of insulin in dogs?

The most common side effect of insulin for dogs is low blood sugar (hypoglycemia). This happens if a dog receives too much insulin or if they don’t eat after they receive insulin. Low blood sugar can be life-threatening.

Signs of low blood sugar in dogs includes:

• Low energy

• Shaking

• Fainting

• Seizures

• Incoordination

• Vomiting

Always keep a container of honey or corn syrup around. If you notice signs of low blood sugar, rub a small amount of honey or corn syrup onto your dog’s gums. Then call a veterinarian or an emergency clinic immediately.

Another common side effect of insulin in dogs is thickening or irritation of the skin where injections are given. This can be reduced by rotating injection sites.

Allergic reactions to insulin are also serious, but they are rare. Signs of an insulin allergy include:

• Swollen face

• Hives

• Vomiting

• Scratching and itchiness

If you notice signs of an allergy, stop giving insulin, and call a veterinarian or an emergency clinic immediately.

Does insulin interact with other dog medications?

Insulin can interact with other medications and hormone therapies for dogs. Insulin should be used with caution when given at the same time as:

• Beta blockers, such as atenolol and carvedilol

• Blood thinners, like clopidogrel

• ACE inhibitors, such as enalapril or benazepril

• Calcium channel blockers, such as amlodipine or diltiazem

• Diuretics, like furosemide

• Digoxin

• Asthma medications, such as terbutaline or albuterol

• Steroids like prednisone

• Estrogen or progestin

• Sulfonamide antibiotics, such as sulfadimethoxine

• Thyroid medications, such as levothyroxine 

• Short-acting sedatives, such as acepromazine, xylazine, or dexmedetomidine

Always tell a veterinarian about medications and supplements your dog takes before they are prescribed insulin. 

How much does insulin for dogs cost?

The exact cost of your dog’s insulin will depend on factors such as the brand and how much they need to take. This chart will give you an idea of how much one bottle of insulin costs.

You will also need to purchase syringes to give your dog their insulin. Here is the cost for the two common syringe sizes.

Why trust our experts?

Written by:

Sarah J. Wooten, DVM, CVJ

Dr. Sarah Wooten, DVM, CVJ, is a well-known international influencer in the veterinary and animal healthcare spaces. She has 16 years of experience in private practice and more than 15 years experience in veterinary media work.

Edited by:

Renée Fabian, MA

Renée Fabian is the senior pet health editor at GoodRx. She’s worked for nearly 10 years as a journalist and editor across a wide range of health and well-being topics.

Reviewed by:

Ghanasyam Bey, DVM

Ghanasyam Bey, DVM, is from Cleveland, Ohio, and attended Princeton University for undergraduate studies. After a year of biology research at Duke University, he attended Ohio State College of Veterinary Medicine.

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