Insulin dysregulation (ID), a condition with excessive hyperinsulinemia, is the most common cause of laminitis in the horse. Insulin dysregulation is a core component of equine metabolic syndrome. Management strategies for ID include feeding diets low in non-structural carbohydrates, but excessive hyperinsulinemia is difficult to manage. There is thus a need for pharmacological treatment of ID. Canagliflozin, a new drug available in humans for treatment of type 2 diabetes, offers a novel therapeutic option for treating excessive hyperinsulinemia in the horse by inhibiting renal glucose reabsorption leading to urinary excretion of glucose. The overall aim of the present study is to investigate if a 4-week period of daily treatment with different doses of canagliflozin attenuates the hyperinsulinemic response to oral carbohydrates in insulin dysregulated horses to a level that would prevent insulin induced laminitis. In addition, any side effects during treatment will be documented.