When preparing equine athletes for peak performance, good nutrition is as important as high-quality training. At the Purina Animal Nutrition Center, in Gray Summit, Missouri, nutritionists set out to determine how an amino-acid-based supplement could support muscle development, proper recovery, and fitness in working horses. Over a 56-day study, the researchers examined the supplement’s effects on a group of Thoroughbred and Quarter Horse mares and geldings.

Managing Research Horses

“Our horses are specifically selected for performance potential,” said Mary Beth Gordon, PhD, Senior Director of Equine Technical Innovation at Purina. “We use Thoroughbreds—many with racing backgrounds—and Quarter Horses from our in-house breeding program. These are horses bred for sport, and we train them to run on a treadmill with all the scientific gear hooked up. It’s about getting the most accurate data possible.”

The trial compared horses fed alfalfa pellets (control group) to those receiving Purina® SuperSport® Amino Acid Supplement. All horses ate the same base diet of Strategy® GX and grass hay, and both groups ate equivalent amounts of protein per body weight. The goal was to evaluate the effects of SuperSport® supplement’s proprietary blend of high-quality amino acids, vitamins, and minerals on the horses’ body condition and fitness.

The horses followed a tightly managed routine: stalled overnight, turned out during the day, and exercised on an Equi-Ciser (a free-run horse exerciser) three to four times per week. “We monitored their heart rate with Polar monitors to ensure they were working at 65% of their maximum heart rate—just the right zone for improving fitness without overtraining,” Gordon said.

Studying the Effects of Purina® SuperSport® Amino Acid Supplement

To assess the effects of supplementation, researchers tracked multiple indicators. These included changes in body weight and body condition score, muscle mass assessments, and detailed measurements such as forearm and gaskin circumference.

The horses in the treatment group accepted the supplement without issue. “They ate it readily,” said Gordon. “That’s always something we monitor closely, especially when introducing new ingredients like highly digestible whey and soy proteins.”

As the treatment horses showed optimal fitness from the program and supplement, they were happy to work, Gordon said. “They felt good, acted more athletic, and clearly enjoyed moving their bodies. That’s what every owner and trainer wants to see.”

Study Takeaways and Practical Applications

From the perspective of a nutritionist and equine scientist, Gordon said what stood out most was the clarity of the results. “We do plenty of research that doesn’t produce a measurable effect,” she noted. “But this one did. It’s rewarding to see a supplement that really makes a difference, both in the data and in how the horses feel and perform.”

In the field, not every horse will respond identically, but the research underscores the value of pairing the right nutrition with consistent training. “SuperSport® supplement works best when the horse is in an active exercise program,” said Gordon. “You can’t expect results just by feeding it in the pasture. But with the right approach, this supplement can help horses feel their best and look the part of a fit, capable athlete.”

If you’re unsure about your horse’s nutritional needs, work with a qualified equine nutritionist or talk to a Purina PhD nutritionist for support.