A recent study in 2024 reported that spirulina enriched with certain trace minerals could increase insulin sensitivity and lower insulin numbers in insulin resistant horses. This further developed research that was previously published.
This is important because high insulin levels are frequently accompanied by laminitis.
◆︎ What did the study show?
Spirulina lowered insulin levels in a challenge test after 3 months of supplementation. The actual pelleted spirulina fed was at the rate of 20 grams of spirulina/100 kg of body weight or 90 grams (3.2 oz) for a 1000 lb horse.
The study also showed:
☛ Lost weight. Prior to the supplementation, the horses that received spirulina were considered obese. During the 3 month study, they lost weight. This was also closely tied to a reduced body condition score after supplementation.
☛ Reduced cresty neck size: Compared to before supplementation, the cresty neck size was reduced after the supplementation.
☛ Reduction in the level of inflammatory cytokines: Two major cytokines, TNF-α and IL-1b were reduced after supplementation.
☛ Increased insulin sensitivity after supplementation.
Sounds great? It is – for those horses.
◆︎ But does this work in the “real world”?
Several people have tested to see if insulin levels could be improved in horses in the “real world”. What was found is:
➡ For some horses that consumed that level of spirulina, their insulin levels improved drastically, as well as hoof comfort.
➡ For some horses that consumed that level of spirulina, their insulin levels didn’t change.
➡ Some horses found that level of spirulina in food was inedible and were not able to achieve that level.
Obviously, more research is needed.
◆︎ Strategies to improve chances of successfully lowering insulin numbers.
➡ When first introducing spirulina, start small, with just a pinch. The smell is new and takes time to get used to it. Sometimes it helps to sprinkle a little on their hay or in their stall to get them accustomed to the smell.
Some people, whose horses readily eat spirulina, find that the powder is too difficult to manage because it gets everywhere. For horses who don’t object to spirulina, the spirulina tablets are a cleaner choice and easier to handle.
Build up to the 90 grams instead of trying to get the horse to accept it with an abrupt change.
➡ Be sure that other foods are low in sugar and starch. When possible, test the hay, and find suitable hay that is low in sugar (ESC) and starch. If the hay is higher than 10% sugar (ESC) + starch OR if you are unable to test the hay, soaking the hay may be beneficial to reduce the sugars.
➡ Be sure that any treats fed should be low in sugar and starch.
➡ Exercise if your horse is able. Exercise is excellent at lowering insulin levels in horses. However, if your horse is footsore or laminitic, don't exercise because the trauma to the hoof can damage the lamina.
➡ If these strategies are not successful in lowering insulin levels, talk to your vet about adding medication, such as metformin or the "-flozin" drugs.
We do the best that we can for our horses. New research on factors that can affect insulin levels are a part of that.
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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