ProZinc vs Insulin glargine: what's the difference?
How ProZinc and Insulin glargine compare: what each is for, how it works, side effects and cost, side by side.
Last updated: October 2026 · 4 sources · see sources
Side by side
| ProZinc | Insulin glargine | |
|---|---|---|
| Generic name | Protamine zinc insulin | Insulin glargine |
| Brand names | ProZinc | Lantus, Basaglar |
| For | Dogs and cats | Dogs and cats |
| Prescription | Prescription | Prescription |
| Used for | An injectable insulin approved for diabetic cats and dogs. [1] | A long-acting human insulin used mostly in diabetic cats. [2] |
| How it works | It replaces insulin so the body can move sugar out of the blood. The added protamine and zinc make it last longer. [1] | It releases slowly from under the skin to keep blood sugar steadier. [2] |
| Common side effects | Lumps at injection sites. The main risk is low blood sugar. [1] | Skin lumps at injection sites. Low blood sugar is the main danger. [2] |
| Use with care | Signs of low blood sugar include weakness, wobbliness, trembling and seizures; call your vet right away. Don't inject if your pet isn't eating unless your vet says to. [1] | Not for pets that aren't eating or have low blood sugar. Ask your vet before changing insulin or syringe type. [2] |
| Typical price | Insulin for a dog (any type): $30–$150 a month [3] Insulin for a cat (any type): $50–$150 a month [4] | Insulin for a dog (any type): $30–$150 a month [3] Insulin for a cat (any type): $50–$150 a month [4] |
| Full guide | ProZinc (PZI insulin) guide | Insulin glargine (Lantus) guide |
Key differences
On the basics they are alike: same kind of animal, same way to get them. The differences are in how they work and what else they cover, shown in the table above.
Which one is right for my pet?
That is a call for your vet. They weigh your pet's age, weight, other health problems, other medicines and what you can realistically give at home.
Switching from ProZinc to Insulin glargine is common, but do it only with your vet's plan.
Common questions
What is the difference between ProZinc and Insulin glargine?
Both are insulins used in diabetic cats. ProZinc is approved for cats and dogs; glargine is a human insulin used mostly in cats.
Is ProZinc better than Insulin glargine?
Neither is better for every pet. Your vet chooses based on your pet's species, age, health history, other medicines and what you can manage at home.
Can my pet take ProZinc and Insulin glargine together?
Only if your vet says so. Some medicines in the same family should not be combined, and others are often used together. Always check before adding or switching.
Do ProZinc and Insulin glargine need a prescription?
ProZinc: Yes. It needs a prescription from a veterinarian. Insulin glargine: Yes. It needs a prescription from a veterinarian.
How much do ProZinc and Insulin glargine cost?
ProZinc: Insulin for a dog (any type) $30–$150 a month. Insulin glargine: Insulin for a dog (any type) $30–$150 a month. Prices vary by pet size, pharmacy and clinic.
Related
This page is general information for planning, not veterinary advice. Talk to your vet about your own pet.