Do you own a cat with Feline Diabetes Mellitus? If yes, then you should know that most diabetic cats require insulin therapy as part of their treatment, and improving their diet alone won’t fix it. Since the majority of diabetic cats require insulin, you must choose the best insulin for cats available.
When Do Cats Need Insulin?
Diabetic cats are growing every year due to the abundance of cat food options and loving parents. Diabetes Mellitus is a condition in which the body cannot produce sufficient insulin to control blood sugar levels. Without treatment, high blood sugar can lead to depression, weight loss, dehydration, vomiting, and even death.
Feline Diabetes Mellitus can be temporary or permanent depending on your cat. With insulin therapy and proper diet, there is a fair chance of reversing the condition. However, the condition can return even years after diagnosis.

The 5 Best Insulins for Cats
There are several types of insulin available. Some are designed for humans but can work on pets, while others have been developed for animal use only. Human pancreatic have slightly different structures than animal pancreatic cells. So, the insulin they produce naturally is different. Due to this difference, human insulin isn’t always effective in pets.
Choosing the best insulin for cats depends on many factors such as availability, effectiveness, preferences, and professional recommendations, etc. However, according to many veterinary internal medicine specialists, here the seven types of insulin for cats available in the market:
1. Glargine
Many veterinarians recommend Glargine (Lantus, made by Sanofi Aventis). Lantus is a human insulin that works very well on cats. However, it works effectively with the combination of a low-carb canned food diet (less than 7% carbohydrates). Glargine is the only insulin that offers a chance of remission, meaning that your cat may no longer require insulin.
The dosage required depends on your cat and its blood sugar levels.Most cats require 1 or 2 units twice daily. However, the chances of remission are slimmer with a single daily injection, but it is an option for cat owners that cannot afford two daily injections.
2. Lente Insulin (Caninsulin/Vetsulin)
Lente insulin is an intermediate-acting insulin that you can commonly find in the market as Caninsulin or Vetsulin (made by Merck Animal Health). It is a porcine-derived insulin for cats with a concentration of 40 U/mL in contrast to 100 U/mL registered for humans. This insulin has an 84% success ratio based on owner satisfaction according to a study by DovePress.
However, it has a low remission rate due to the short duration of Lente action after administration, even with two daily dosages.
3. Neutral Protamine Hagedorn (NPH)
This is isophane insulin that is made for humans but also useful in cats. You can find it in stores as Humulin N (manufactured by Eli Lilly) or Novolin N (manufactured by Novo Nordisk). Although it is not as likely to induce remission as glargine, NPH is relatively less expensive making it an economical option for cat owners on a budget.
However, the dosage of NPH for diabetic cats depends on your cat’s weight so owners have to regularly check and adjust it to ensure they meet the proper requirement.
4. Protamine Zinc Insulin
Protamine Zinc insulin was a pork/beef insulin market for cat use in insulin therapy by the name PZI VET (manufactured by IDEXX). It was removed from the market but many compounding pharmacies continue to produce it.
However, veterinary endocrinologists do not recommend its use and promote ProZinc (manufactured by BoehringerIngelheim) instead. This is a recombinant human PZI insulin specifically designed for cats, and it is incredibly safe and effective.
5. Detemir
Detemir is a human recombinant insulin available in the market as Levermir (manufactured by Novo Nordisk). It works in a similar way to glargine and it is effective in cats. While a single daily dose is sufficient for humans, its duration of action in healthy cats is shorter so you’ll need two daily dosages.
According to a study, 11 cats underwent detemir insulin therapy and 9 of them went into remission which is an 81% success ratio. However, the rate of remission depends on how long your cat has been diabetic.
How to Choose the Best Insulin for Your Cat
When choosing the best insulin for cats, veterinarians have several options among those formulated for humans and those developed and approved by veterinary use. Veterinary companies spend resources to have the FDA approve their products for canine and feline use.
They design these products specifically for cats and dogs to benefit from their use – they are for humans. The American Animal Hospital Association (AAHA) recommends veterinarians to use veterinary FDA-approved products to treat animals because they would be most beneficial for animals.
For cat owners, it is also important not to change or discontinue your cat’s insulin without consulting your vet. Secondly, if your vet advises you to make a change, make sure you use the correct syringe type for that specific insulin brand. Human insulin syringes are 100 units per milliliter while veterinary insulins are 40 units per milliliter.
Lastly, if your cat is newly diabetic, try to avoid high starting doses, especially if they’re overweight. Remember to round your cat’s bodyweight down to the nearest kilogram and the dose down to the nearest whole or half unit.
Diet for Diabetic Cats
Insulin therapy won’t be effective without a proper diet plan for your diabetic cat. Cats are carnivorous and their daily energy intake is 2% carbohydrate, 52% crude protein, and 46% crude fat. However, commercial feline food diets have up to 60% of their energy from carbohydrates.
Cat’s bodies aren’t as good as humans at breaking down carbohydrates, so it’s the owner’s job to ensure that their diet includes lots of proteins.
Our Final Thoughts
Remember that every cat is an individual so ultimately, it is up to your vet to decide which insulin is suitable for it. But considering all the options, Glargine is the best insulin for cats in terms of effectiveness and owner satisfaction.