Hot summer days. The temperature reaches 100°F. The nights are hot and don’t cool down sufficiently. We’ve taken all the steps necessary to help our horses cope with the heat. But what about our supplements in the barn?
◆︎ The Danger to Oil-Based Supplements in the Heat
Heat breaks down oils. How susceptible an oil is to degradation depends entirely on its chemical structure. So, what does this mean for the supplements sitting in your tack room?
Scenario 1: Two Weeks in the Heat
You bought a jug of liquid Vitamin E. You are doing all the right things, but the jug stays in the feed room where summer temperatures regularly reach 100°F. The oil immediately begins to oxidize (go rancid). Because there is Vitamin E in the liquid, the vitamin sacrifices itself to slow down that oxidation. After just two weeks, you may think you are feeding your horse 2,000 IU of Vitamin E, but you are likely only delivering 600 to 700 IU. The rest was destroyed trying to protect the oil.
Scenario 2: Six Weeks in the Heat
The temperatures are still hovering around 100°F, and six weeks have passed. The oil continues to degrade, and your Vitamin E continues to fight the oxidation. At this point, your 2,000 IU dose could be reduced to a mere 100 to 300 IU.
◆︎ The Ultimate Supplement Wishlist
Wouldn’t it be great if there was a Vitamin E powder that checked all these boxes?
☑ Heat stable
☑ No additional dietary oil necessary for absorption
☑ Can be pre-mixed in baggies with other supplements
☑ Readily absorbable in the gut
☑ Provides the natural (d-alpha) form of Vitamin E
◆︎ The Solution
My Best Horse now carries Vitamin E Zsorb, a microencapsulated powder that fulfills that exact wishlist.
◆︎ How Vitamin E Zsorb Works
The fragile natural Vitamin E is locked inside a specialized, dry carbohydrate matrix. Because it is encapsulated and dry, it is highly heat-stable in the barn. When the powder hits the horse's stomach, the outer shell instantly disperses the Vitamin E into a microscopic emulsion. This allows the digestive enzymes to rapidly unlock the vitamin, transporting it across the intestinal wall with an incredibly high absorption rate—no messy oils required!
◆︎ Types of Vitamin E
As a refresher, synthetic Vitamin E (often listed as dl-alpha) is a mixture of eight different stereoisomers. When your horse digests this synthetic mixture, their liver actively filters out and rejects the majority of these synthetic isomers, searching for the single natural form (d-alpha). This means you have to feed significantly more of a synthetic powder just to achieve baseline antioxidant levels.
Vitamin E Zsorb is manufactured using only the natural d-alpha form. Because the horse's body recognizes it perfectly, you can feed less volume while achieving the exact blood levels your horse needs.
◆︎ Can’t we just use the micellized liquid version of Vitamin E in the heat?
The short answer is no. Micellized liquids are suspended in an aqueous (water-friendly) solution without a protective chemical cap. Because they have zero chemical or physical protection from the heat, they break down rapidly. You may find that after two weeks of elevated temperatures at 100°F, you have only 50% of the amount of active Vitamin E remaining. After six weeks, you may be left with 20% or less!
◆︎ Take-Home Note:
For reliable heat stability and absorption, Vitamin E Zsorb can’t be beat. Your horse deserves the very best. Stop letting the summer heat steal your supplements!
We do the best we can for our horses. Understanding our horse's needs 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, MSc. 2026