In our last newsletter, we discussed strategies for lowering insulin levels in horses. Available here. A number of suggestions were provided to help the horse. However, there are some horses that do not respond sufficiently to dietary changes and/or have limited ability to exercise. As discussed in that article, they may be candidates for therapeutic drugs.
◆︎ Why do we care about insulin levels?
An elevated insulin level frequently results in laminitis or footsoreness. Reducing the insulin levels frequently alleviates the pain. Last week, we mentioned two drugs that may help reduce insulin in horses.
◆︎ Metformin:
Metformin at the recommended dose of 35 mg/kg body weight twice a day. Many people have found this to be effective. Two drawbacks to this drug:
➡ It may cause mouth irritation upon syringing the ground tablets. It is advised to give with milk of magnesia to help coat the mouth. Additionally, rinsing the mouth with plain water afterwards may be helpful.
➡ Many people have found that metformin works quite well initially, but then the insulin levels creep back up over about a month.
The advantage to this is that it’s readily available and fairly inexpensive. If your horse has laminitis from the lush spring grasses, this may be a suitable short-term solution.
◆︎ -Flozin drugs:
A class of newer drugs, SGLT2 inhibitors, are available to help lower insulin levels. The two common ones for horses are:
➡ Ertugliflozin: administered at the dose of 0.05 mg/kg daily or
➡ Canagliflozin: administered at the dose of 0.3-0.6mg/kg daily
Although these drugs can make a tremendous difference, it’s important to be vigilant about your horse care practices. Potential side effects should be monitored, such as elevated triglycerides and liver enzymes, along with weight loss.
◆︎ What they do:
The -flozin drugs cause glucose to be excreted in the urine. This lowers the glucose level, with the insulin level then lowering. But the problem is that the horse still needs energy to function. If the glucose level gets too low, the body then sends signaling molecules to say that it doesn’t have enough energy. Triglycerides are then released in response to those signaling molecules. This can result in elevated triglyceride levels, along with elevated liver enzymes. We want to avoid this. The following protocol is appropriate for horses on -flozin drugs, to reduce the risk of high triglyceride levels and elevated liver enzymes.
◆︎ Protocol for supporting the horse on the -flozin drugs:
➡ Additional salt: The -flozin drugs dump glucose into the urine. Because of this, it’s important to keep your horse well-hydrated. Salt encourages the horse to drink. Consider 2 tablespoons per day for a 1000 lb horse. Some horses may object to that level of salt in their bucket. Dampening the hay and sprinkling salt on the dampened hay is another effective way to add more salt to the diet. If a salt block is their only source, you won’t know exactly how much the horse is getting. Good hydration is important.
➡ Not soaking hay: Soaking hay could potentially cause the glucose levels to drop too low, and cause the body to the signal that it is fasting. Fasting may cause a rise in triglycerides. Additionally, consider free-choice hay.
➡ Add beet pulp: Beet pulp is fermented in the hindgut and does not spike the insulin levels like grains do, yet still provides energy for the horse. Consider adding 2 lbs of beet pulp per day (dry weight). This will add energy for the horse without the insulin spike. You may need to rinse/soak/rinse the beet pulp to remove dirt and iron. Beet pulp is not a low calorie food.
➡ L-Glycine: Glycine is an amino acid that supports normal glucose levels in the body and supports energy metabolism. Feed at the rate of 100 grams/ 1000 lbs of body weight per day. If possible, feed it in two or three feedings throughout the day. (If two feedings, 50 grams at each feeding. If three feedings, about 33 grams at each feeding.)
➡ L-Carnitine: Feed at the rate of 10 grams of Carnitine / 1000 lbs of body weight per day. L-Carnitine supports the metabolism of fats and triglycerides. By supporting the metabolism of fats and triglycerides, the liver is also supported.
➡ Milk thistle: If mild elevation of liver enzymes occur, milk thistle may be able to support the horse. With significant elevation of liver enzymes, work with your vet to find alternative solutions, or stopping the use of the drug.
➡ Fly control: You will want to be meticulous about your fly control, especially in warmer weather. With glucose dumped in the urine, some people have found that the fly population seems to be worse than normal.
◆︎ Work with your vet:
Working with your vet is critical. It’s important to monitor the levels of triglycerides and liver enzymes. You don’t want to be accidentally creating other problems besides the ones you already have.
The protocol to help your horse isn’t difficult, just different. Being aware of the dietary changes for horses on -flozin drugs is important. We do the best that we can for our horses. Understanding options available to us for controlling insulin levels is a part of that.
Do you have a special photo or story that you’d like to share? Email to sales@mybesthorse.com
Disclaimer: Statements regarding dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease or health condition.
©Joan Kulifay 2025