Question: My mustang has very high insulin levels. His blood test result was ACTH 28.0 pg/ml and Insulin >200ulU/ml. I have him on grass hay and low starch grain. What can you recommend for a supplement to help lower his insulin? Dr. Kellon: Mustangs are very prone to high insulin when in captivity.  In the wild, they will cover to 10 to 20 miles a day to get enough food but won't get that much exercise when domesticated unless in endurance training. The first step to lowering the insulin is to make sure the diet is very low in sugar and starch.  "Low" starch grains are usually still much too high compared to the mustang's natural diet of grasses only. I would stop feeding that. You also need to make sure your hay is low enough. The target is below 10% sugar (ESC) and starch combined. You can only be sure of this if you have your hay analyzed. Otherwise, soak it for 30 to 60 minutues before feeding. This will lower sugar.  Feed him 1.5% of his current weight (1.5 lbs of hay per 100 lbs of body weight) or 2% of his ideal body weight (2 lbs of hay per 100 lbs of weight) - whichever is larger. If he is not lame, exercise is important for getting insulin down too. Aim for at least 30 minutes/day of uninterrupted trotting as a minimum. There are no supplements that will directly lower insulin but there are many nutrients that are important for insulin to work properly. If you have your hay analyzed we can tell you what minerals you need to add and in what amount.  In the meantime, Glycocemic EQ supplement will get you off to a good start.