Supplements of Benefit to the Performance Horse (Book Excerpt)

Editor's Note: This is an excerpt from Understanding Equine Preventive Medicine by Bradford G. Bentz, VMD. This book is available from

An increase in exercise also directly increases the needs for vitamins A, E, B-1, and for folic acid. Vitamin E and selenium supplementation may help decrease oxidative damage from energy production.  Adding 1mg of selenium and 1,000 IU of vitamin E to the daily diet may provide selenium and vitamin E supplementation. Only using salt mixes that contain selenium is an alternative way of providing the element.  A balanced vitamin supplement may best provide the additional needed vitamins. However, once again, it is important not to overestimate the intensity of exercise and competition your horse performs so that you do not oversupplement with potentially harmful levels of these additives and you do not waste money.

Support of the need for or benefit of a number of commonly used supplements appears limited. Hematinics or "blood builders" such as iron or vitamin B-12 and vitamin C do not appear to provide any benefit to performance horses.  Administration of such vitamins and minerals may be best reserved for specific instances when a deficiency of these dietary elements is diagnosed.  Several other supplements routinely used to benefit performance horses have little or no evidence supporting their use. Some of these include MSM (methyl sulfonyl methane), DMSO (dimethylsulfoxide), octacosanol, the enzyme super oxide dismutase (SOD), gamma hydroxybutyrate, gamma oryzanol, bioflavonoids, inosine and carnitine, pangamic acid, and some drugs such as nandrolone and amphetamine. Despite lacking scientific support, some have received significant testimonial backing. Of these compounds, MSM and DMSO apparently received significant support from many laypeople and many veterinarians.

About the Author

Bradford G. Bentz, VMD, MS, Dipl. ACVIM, ABVP (equine)

Brad Bentz, VMD, Dipl. ACVIM, ABVP, ACVECC, owns Bluegrass Equine Performance and Internal Medicine in Lexington, Ky., where he specializes in advanced internal medicine and critical care focused on helping equine patients recuperate at home. He’s authored numerous books, articles, and papers about horse health and currently serves as commission veterinarian for the Kentucky State Racing Commission.

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