Are amino acids the future of hydration drinks?

There’s a contradiction at the heart of the growing hydration market. It’s not about what electrolytes to include in drink mixes, but what else to include to help those electrolytes do their job better. 

On one hand, sugar (in the form of glucose) has long been considered to be a mandatory inclusion in hydration products because it can help promote active transfer of electrolytes like sodium, calcium and potassium across cell walls. On the other hand, 71% of regular hydration beverage buyers said they “always look for products with lower sugar,” according to the 2023 NBJ Sports Nutrition and Weight Management Report.

Interestingly, recent research is showing that sugar isn’t the only effective option to boost hydration—and it may not even be the best choice. Certain amino acids are showing the potential to serve the same function as glucose, delivering equal or better hydration with fewer of the unpleasant side effects that sometimes accompany high-sugar drinks.

Low osmolality means better hydration

One way to measure the effectiveness of hydration products is through osmolality tests, which can show the absorption of particles like electrolytes in the blood. Decades ago, the World Health Organization established a standard of osmolality of 311 mmol/kg, applicable to an ideal hydration beverage. A drink testing higher than that standard, by contrast, signifies that less fluid and electrolytes are being absorbed. By comparison, human blood has an osmolality between 275-295 mmol/kg.

A July 2019 study in Nutrients tested a range of popular commercial hydration blends, including big names like Pedialyte and Gatorade, and found they were significantly higher than the WHO standard.

The only product that beat the WHO standard and outperformed water was Enterade, a product currently used primarily in medical settings. This hydration drink, created by Entrinsic Bioscience, contains a proprietary blend of the amino acids valine, aspartic acid, serine, threonine and tyrosine—and no sugar whatsoever.

The research, and another recent study where Entrinsic’s amino formula outperformed Pedialyte, show definitively that sugar actually isn’t necessary to boost hydration, says registered dietician Douglas Kalman, Ph.D.

“Many brands end up selling flavored water that is not really as functional for hydration as they think,” Kalman said in an interview. “Looking to amino acids is truly a pivot, and perhaps a game-changer within the sports and hydration world.”

How do aminos boost hydration?

“There are receptors in the intestine that pull glucose into the bloodstream. When it gets pulled through the intestine, glucose carries sodium as well,” noted Robert Kenefick, Ph.D., senior vice president of research and development at Entrinsic, in an interview with Natural Products Insider. “And wherever sodium goes, water follows.”

This is the logic behind nearly every commercial hydration product on the market, but it has a limitation: glucose can only carry so much with it, and adding more glucose doesn’t make it work better. In fact, some research shows that an excess of glucose can even decrease electrolyte absorption.

“With glucose, it’s like you’re operating on a two-lane highway. It carries two molecules of sodium for every molecule of glucose,” Kenefick said.

“But when you’re dealing with this precise blend of amino acids, each one has its own lane, and some can carry three molecules of sodium apiece,” he added, commenting on Enterade’s product formulation. “It’s like driving on an 8-lane highway, and the net effect is that you get more sodium, and more fluid, where you need it, faster.”

Enterade is currently available in two formulas: an Advanced Oncology Formula for patients undergoing cancer treatment, and IBS-D formula for those suffering from irritable bowel syndrome (although both are available online without a doctor’s prescription as well). But recent research is showing that amino acid-based hydration may be ready to extend into sports as well. 

Hydration without intestinal distress

One side effect of high osmolality, sugar-rich sports drinks is they pull water into the digestive tract. This can contribute to some unpleasant side effects, especially in combination with added stressors that accompany intense athletic training in the heat.

“During extensive or exhaustive exercise, the body won’t digest and absorb nutrients in the normal, healthy manner,” Kalman noted. “This often leads to gut inflammation and discomfort, but also diarrhea, which can wreak havoc on an athlete’s ability to do their sport and make it harder to maintain normal hydration during or after the event.”

Most recommendations to prevent gastric distress and the so-called “runner’s trots” during training or races focus on avoiding certain foods, like high-fiber or high-FODMAP foods. But Kalman said hydration beverages are also a likely contributor.

“Sugar-based hydration beverages only make the situation worse,” he added. A number of studies have shown this to be the case in medical settings, where glucose-containing beverages can actually exacerbate diarrhea.

By contrast, a May 2023 study in the International Journal of Sport Nutrition and Exercise Metabolism found that athletes training in the heat who utilized Entrinsic Bioscience’s Ultra-Hydrating HeatDefense amino acid blend exhibited lower systemic and gut inflammation. They also didn’t experience the customary gastric distress symptoms that accompany heat exertion.

“Combining certain amino acids with electrolytes can soothe the disturbed gut while enhancing hydration without any sugar, something that until recently was not even thought to be possible,” Kalman said.

According to Kalman, the next step in amino acid-based hydration research is to see how this potential extends beyond sports.

“It would be great to see more research on these types of amino acid-based products for hydration in other situations besides extreme exercise, or exercise in a hot environment,” he said. “I’d like to see how it can impact mood states, cognitive function, and other measurements of quality of life. This is an exciting new look at how we can hydrate and perform to the best of our abilities.”