If you have recently embarked on a journey to optimize your dog’s health, well-being, and lifespan, you have likely already encountered the term insulin. And if your vet has diagnosed your dog with diabetes then you definitely have.

That said, insulin isn’t something that you hear much about in mainstream pet food discourse and you’re unlikely to ever see it discussed in your favorite brand’s advertising and labeling. But that’s a problem! Why? Because insulin is far more important to your dog’s health than, say, the manufacturing process used to produce a pet food or whether the food contains grains. 

With these things in mind, we wrote this article to help teach you everything you need to know about insulin for your dog. 

What is Insulin and Why Is It Important to Your Dog’s Health?

Insulin is a signaling hormone produced by the pancreas, in humans as well as cats and dogs. Its primary function is to get glucose (“blood sugar”) out of the blood and into other tissues (such as fat and muscle), where the glucose can be stored safely. This is an essential bodily function, meaning that your dog cannot live without it. Why? Because glucose is highly toxic in even moderately high quantities and rising blood sugar levels will cause horrible health problems (and eventually death) if they aren’t properly controlled by insulin.

The way insulin performs this function is reasonably straightforward. Whenever blood sugar levels get too high (like after your dog eats a carbohydrate-rich meal), the pancreas automatically begin secreting insulin. (At least if your dog has a normal, healthy metabolic system.) The hormone then circulates throughout the bloodstream, signaling to specific organs (like the skeletal muscles and body fat) that they need to begin absorbing and retaining more glucose than they otherwise would. Then these other organs soak up some of the circulating blood sugar, the blood tests levels come back down, and insulin secretion ceases.

Insulin and Diabetes Mellitus

Understanding insulin is particularly important for owners of dogs and cats with the disease diabetes mellitus. Diabetes comes in a few different flavors (in humans we call the main ones “Type I” and “Type II” and in cats and dogs there are other subtypes). But in all cases, the fundamental problem is the same: the animal cannot produce enough insulin to properly regulate its blood glucose. So when a diabetic dog eats a carbohydrate-rich meal, its blood glucose levels stay too high, raising the prospect of all manner of health problems.

Because diabetic dogs aren’t very good at producing insulin on their own and properly regulating blood sugar, one of the primary treatments for diabetes is administering insulin injections to help supplement the weak insulin response. Insulin supplied through these injections is called “exogenous,” meaning that it comes from outside of the body (in contrast, insulin naturally produced by the pancreas is said to come from an  “endogenous” source).

In other words, exogenous insulin is a kind of drug/medication that is manufactured by companies and sold to pet owners and vets, who then provide it to dogs and cats, typically via injection.

Insulin for Dogs

Insulin therapy is the primary treatment for canine diabetes and involves administering insulin to replace the missing or ineffective hormone. The goal of insulin therapy is to help regulate blood glucose levels and prevent complications associated with diabetes, such as blindness, kidney damage, and nerve damage.

How To Know If Your Dog Needs Exogenous Insulin Injections

Conceptually, you will need to give insulin shots to your dog if that animal’s blood sugar isn’t coming down to sufficiently low levels after eating carbohydrate-rich meals or spiking for other reasons. (See this article for more on what constitutes “sufficiently low” blood sugar levels).

In practice, your vet will tell you. If your dog begins showing symptoms of diabetes, you’ll want to bring the animal to the vet for testing and diagnosis. Your vet will measure the animal’s circulating blood glucose and insulin concentration and use those to determine if the animal has diabetes.

Insulin Dose for Dogs

As for determining the appropriate insulin dose, your vet will give you an initial estimate but you should expect to go through some amount of trial and error before settling on your dog’s regular insulin treatment dose. The size of your dog, the severity of its disease, the animal’s diet, insulin type, and lots of other factors will influence the appropriate insulin dosage amount. Many dogs need just one daily insulin injection, while others require two.

It is crucial to follow the veterinarian's instructions regarding the dog insulin dosing and the insulin administration itself. Giving the wrong dose of insulin can be dangerous and can lead to serious health complications for the dog.

In order to dial-in the insulin dosage and understand whether the shots are doing their job, pet owners will have to get familiar with measuring their dogs’ glucose levels and interpreting their blood glucose curves. (We discuss how to do this here.) Ultimately, making sure that glucose ends up at a health level is the primary goal – but how much exogenous insulin is required to get there will vary dog-to-dog.

We must reiterate, please consult your veterinarian in order to assess to proper insulin dose for your dog

Your Dog's Blood Glucose Curve

In order to determine the effectiveness of any insulin treatment for your dog, you need to know how to interpret the blood glucose readings you are taking.

Maintaining a glucose curve with a range from 100-250 mg/dl for most of the day will help to minimize diabetic symptoms in your dog. Click the link to read more on glucose curves, how to read them, and why they are important.

Buying Insulin For Your Dog

Insulin injections cannot be purchased over the counter. The hormone is considered a drug in the United States and, as such, can only be purchased with a vet’s prescription.

We've said it before but we will say it again, vets and healthy dogs go hand-in-hand.

What’s the Best Brand of Insulin for Dogs?

Well, there’s pretty much only one insulin therapy for dogs we could consider "The Best". The brand is called Vetsulin and it is made by the mega-pharma company Merck. Vetsulin products are FDA-approved for the treatment of diabetes in both dogs and cats.

It’s an inslulin injection (meaning it is administered as shots, not pills) and it is porcine insulin (AKA derived from pigs). As of 2023, it typically runs about $70 for a 40-unit bottle.

Here is a more comrehensive list of insulin manufacturers that sell insulin used to treat diabetes in dogs.

• Vetsulin®
• ProZinc®
• Caninsulin®
• Novolin®

Some of these products are actually insulin made for humans and have a various duration of action from long to short acting.

If you want to get into more the weeds on some of the various types insulin for dogs and cats then click the link.

Where Can You Buy Insulin for Dogs?

As always, you can purchase your dog insulin at your veterinary hospital.

But if that is not your jam, here is a list of places to purchase your dog's insulin in person and online.

In-Person Pet Pharmacies

• Most Vets
• Petsmart
• Vons
• Walmart

Online Pet Pharmacies

• Chewy
• 1800petmeds
• Petco
• PetMart Pharmacy
• PetCare RX

Of course, you'll still need a prescription to buy the insulin, knowledge on how to administer the injection, and a sense of how much insulin should be administered to your dog (among other things). 

So please, make a trip to your vet ASAP.

Where and How Do You Administer Insulin Injections to Your Dog?

According to the American Animal Hospital Association, the best injection sites to administer an insulin shot are on your dog’s back – about two inches from the spine, near either the shoulder blades – or the hip bones. An Insulin injection is administered by subcutaneous injection (just under the skin). 

Additional information can be found, of course, in the product’s directions and in your vet’s prescription.

Recommended Insulin Syringes & Needles for Dogs

There are two types of syringes used for giving insulin to dogs. Mostly it depends on the type of insulin you're giving. According to VCA Animal Hospital, some insulin brands require a U-40 syringe (such as Vetsulin) while others use a U-100 syringe (primarily human-use insulin brands)..

Typically your veterinarian will provide you with the correct syringes, so you don't have to worry about it. These syringes also already have needles attached to them, so there's no need to worry too much about getting the right needle.

Are There Other Ways to Help Regulate Your Dog’s Blood Sugar?

Yes! You may find that buying exogenous insulin bottles is expensive and that insulin administered via injection is painful and annoying, both for you and your dog.  So you might be inclined to try to lower high blood sugar levels other ways.

The single best method is to reduce the carbohydrate content of the animal’s diet. Studies consistently show that reducing carbohydrate intake tends to lower post-prandial blood glucose in dogs, which means less exogenous insulin is required to bring glucose under control. 

If that sounds appealing to you, check out our product Ketona. It contains 90% less carbohydrate than most other “ultra-premium” kibbles.