Avoid These!
Even a quick look at human exercise/performance supplements will show you there is a huge array. Some work, some don't. Some also are of use in horses, some aren't. Worse yet, the castoffs on the human end, products well known not to be helpful, may end up in equine supplements. Some things to avoid include:
Chromium: Not likely to be deficient and won't help if it isn't. Chromium is important to proper utilization of glucose by muscles, but unlikely to be deficient unless horse is eating hays/grains grown in alkaline soils (Southwest). Horses on high-grain intakes or using glycogen loaders may need more chromium. Heavy exercise also increases chromium losses in other species, but it's not proven in horses.
Inosine: This is a waste product of ATP breakdown, and high levels are harmful to energy generation.
Lactate and Pyruvate: The muscle and liver can utilize these byproducts of carbohydrate metabolism, but there's no shortage of them during exercise and there are much more efficient ways to provide energy.
Creatine: Although creatine is well-documented as useful in human sports medicine to improve intense muscular efforts in humans, the value to horses remains questionable. Equine literature and our own field trials have found no or equivocal results. Very high doses have caused cramping in some horses. It's also expensive. We'll pass.
DMG (dimethylglycine): Although still widely touted as a way to lower lactic acid production, this supplement does not work in people, and there's nothing to support its use in horses either. The precursor of DMG, TMG/betaine does appear to be of benefit to untrained horses starting exercise, or those entering more strenuous stages of exercise training. A 1999 study published in the Journal of Animal Science found horses supplemented with 80 mg/kg of body weight of betaine (40,000 mg for a 500 kg/1100 lb. horse) showed lower levels of lactate production and lower release of fatty acids, indicating more efficient aerobic ultilization of glucose. Betaine also improves muscle bulk while decreaseing fat in other species. However, no performance benefit has been found in horses that are already fit.
Adaptogens: Ginsengs and some other herbs are adaptogens that have been proven to moderate the cortisol response to exercise or stressful situations so that it's more like that of a trained animal and to avoid exaggerated responses. It probably does this by being structurally similar to the mammalian hormones. Horses that are sour, have poor energy levels and appetites often show a favorable response to adaptogens, which includes Ginseng.
Bottom Line
Equine-exercise research is finally starting to catch up with human. Studies have now shown that either intravenous or oral glucose supplementation improves glycogen levels in muscle compared to conventional feeding regimens. So, if you're looking for a true performance enhancer, we'd probably start with muscle builders, including glycogen loaders like maltodextrin, and BCAAs.
Because it's important to choose the product based on your horse's particular needs, it's difficult for us to make a No. 1 pick here. That said, we think the standouts in our chart include: APF, Power Pak, Blitz, BCAA Complex, Carbo Load, CarboCharge, Glycogen Loader and Advanced Glycogen Loader.
