Which of the following is a veterinary-approved insulin product?

Vetsulin is a veterinary-approved insulin product specifically formulated for use in dogs and cats with diabetes mellitus. It contains porcine insulin, which is similar to canine insulin, making it an appropriate choice for managing diabetes in these animals. The formulation is designed to meet the needs of pets, ensuring proper absorption and action within their bodies.

While Novolin and Humulin are human insulin products, they are not specifically approved for veterinary use, although they may be used off-label in some circumstances. Regular insulin, which is a type of human insulin, is also not intended for veterinary use, as it lacks the specific formulation considerations needed for effective veterinary diabetes management. Thus, Vetsulin stands out in this context as the correct choice due to its tailored formulation and specific approval for veterinary use.