Insulin resistance

Veterinary advice should be sought before applying any treatment or vaccine.

Insulin Resistance

Pre-Cushing's, Cushingoid, Syndrome-X, Hypothyroid, Metabollic Syndrome

Insulin resistance (IR) is the main component of equine metabolic syndrome and an important risk factor for laminitis in horses. IR is defined as a clinical state in which insulin-responsive tissues (such as the liver, adipose tissue and muscle) are insensitive to normal or elevated levels of insulin and will accumulate high levels of glucose in their blood instead of transferring it for absorption by cells throughout the body. Low-grade systemic inflammation and oxidative stress are both features of obesity and insulin resistance.


Abnormal fat deposits
Cresty neck
History of laminitis
Eye puffiness
Increased thirst and urination
Poor body condition
Low energy
Muscle wasting


  • History
  • Clinical signs
  • Resting serum insulin concentrations - hyperinsulinaemia is a common feature of IR in horses
  • Combined glucose-insulin test



Weight ManagementObese or overweight horses need to be put on a weight loss program by limiting caloric intake, restricting access to pastures with grass, and increased exercise. Hay should be selected with low NSC content or soaked in cold water for 60 minutes prior to feeding.
Change feedSelect feeds that are low in starch and sugar. It is also better to feed smaller meals more frequently as opposed to two larger meals.
MetforminA drug often used however potential side effects include mild colic and hypoglycaemia when first started.
Levothyroxine sodiumUsed to induce weight loss and improve insulin sensitivity.


  • Ensure horses do not become overweight
  • Provide regular exercise
  • Limit pasture access during periods of rapid grass growth or during droughts
  • Utilize a grazing muzzle if turned out in pasture
  • Minimize amount of concentrated feed in diet, and provide feeds low in starch and sugar

Scientific Research

General Overviews