Does the FreeStyle Libre work on dogs? 


Many vets are increasingly prescribing the FreeStyle Libre for dogs.

What does this mean?

The FreeStyle Libre can be a great tool to assist with tracking BG.

However, is it reliable? Not always. 

So, what exactly is it? It is a small device attached to the body that has a subcutaneous to measure glucose levels. It is made for humans. Currently, the manual has NO mention that it can be used on dogs. And when you call customer service about any issues regarding the product on the dog, they will hammer that into your head as much as possible and repeatedly tell you that if you use it on your dog, it is at your own discretion and issue/faulty products will not be covered. 

Is it harmful to your dog? No.

You might have issues using it on your dog because the FreeStyle Libre is calibrated for humans.


The FreeStyle Libre is not actually looking at blood. The sensor reads the subcutaneous INTERSTITIAL fluid (a thin layer of fluid that surrounds the body's cells.) 

Blood glucose distribution in the interstitial fluid is different in Humans and dogs. 

- Human - 58% BG in plasma and 42% BG in blood 

- Dog - 87.5 BG in plasma and 12.5% BG in blood

Therefore, your BG numbers can vary drastically from doing an actual blood test. 

It can, however, on some dogs cause a rash where the senor is applied to the skin. So repeated use in the same spot can become bothersome for your dog.


The FreeStyle Libre should NOT be a replacement for proper blood testing on your dog.

BUT: It can be incredibly helpful to show BG trends.

- When the insulin tends to peak.

- When your dog's BG tends to spike.

- What changes in temperature does to BG levels

- Potential BG increases due to treats, etc.

Keep in mind the FreeStyle Libre is pricey, given how long it lasts. It says up to 14 days. Typically with dogs, you'll get closer to 10. 

   -   This can depend on how active your dog is,

   -   If the leash/harness rubs against the sensor

   -   It is in a position they can scratch at it. 

You might need to reinforce it with a medical tape overtop the sensor. If you have the money to afford to get 2 to 3 a month, then it yes, it does provide additional peace of mind. When starting out using the FreeStyle Libre, do periodic blood tests to see how BG numbers correspond to the sensor readings. 

Given its potential inaccuracies/inconsistency, it is dangerous to make changes to insulin amounts on the sensor readings alone. Used in conjunction with blood drop testing, it can be helpful for some. 

If your Vet recommends it, know the risks/expenses and be open to trying it out. However, tell them you would still like to do at home blood testing. 

FreeStyle Libre company has mentioned that they are planning on developing a sensor that is made for dogs. Who knows how long that will take.


BUT, they definitely DON'T want to help you if you DON'T use it as intended - on a human.