Are there any drinks that hydrate better than water?

December 4, 2025 •

4 min read

According to a study conducted by Scotland’s St. Andrews University, some beverages can provide longer-lasting hydration than plain water, depending on their composition. The presence of certain nutrients like sugar, fat, and protein can influence how the body absorbs and retains fluids, challenging the popular notion that water is always the optimal hydrator.

Quick Summary

This article explores which beverages, including milk, oral rehydration solutions, and coconut water, are scientifically proven to be more hydrating than plain water for longer periods. It examines the factors contributing to superior hydration, including electrolytes and macronutrients, comparing different options and their specific benefits for various situations, such as post-exercise or during illness.

Key Points

Milk is surprisingly hydrating: Studies show both full-fat and skim milk can be more hydrating than water, thanks to their protein, fat, lactose, and electrolyte content, which slows gastric emptying.
Oral rehydration solutions are best for illness: For dehydration caused by illness like vomiting or diarrhea, ORS formulas offer a superior balance of electrolytes and glucose for rapid rehydration compared to plain water.
Coconut water for lighter activity: With its high potassium content, coconut water is a good option for replenishing electrolytes after moderate exercise but is not necessarily more hydrating than water for everyday use.
Sports drinks are for high intensity: For prolonged, high-intensity exercise where significant sweat and electrolytes are lost, sports drinks can be beneficial, but are often high in sugar and calories.
The role of electrolytes: The presence of electrolytes like sodium and potassium in a beverage is crucial for improving fluid retention and balancing the body's fluid levels.
Caffeine and alcohol's diuretic effects: Moderate amounts of coffee or tea are generally as hydrating as water, but excessive caffeine intake and strong alcoholic drinks can have a mild diuretic effect, increasing fluid loss.
Water remains the daily standard: For general, low-intensity activities and normal hydration needs, plain water is the best, most accessible, and calorie-free choice.

The Science of Hydration: Why Some Drinks Outperform Water

While water is the undisputed gold standard for everyday hydration, the body's ability to absorb and retain fluids is a nuanced process. This is where certain drinks can actually provide a hydration advantage over plain water, particularly in specific circumstances like intense exercise or illness. The key lies in the presence of electrolytes, such as sodium and potassium, and macronutrients like carbohydrates, protein, and fat. These elements influence the body's osmolality—the balance of solutes and water—and can slow gastric emptying, leading to a more prolonged and effective rehydration process. For instance, a beverage containing electrolytes encourages the body to hold onto fluid, reducing the rate at which it is lost through urination.

The surprising contender: milk

In studies comparing the hydration efficacy of various beverages, milk consistently scores higher than water on the Beverage Hydration Index (BHI). Both full-fat and skimmed milk demonstrated superior hydration for longer periods due to a few key factors. Its combination of protein, fat, and lactose (a sugar) slows down fluid absorption, prolonging the hydration effect. Additionally, milk's natural sodium content acts like a fluid magnet in the body, helping to retain water. This makes milk an excellent post-workout option to replenish fluids and electrolytes lost through sweat.

The medical standard: oral rehydration solutions (ORS)

For rehydration following severe fluid loss from diarrhea or vomiting, Oral Rehydration Solutions are medically proven to be more effective than water. These solutions contain a precise balance of electrolytes (sodium, potassium) and glucose, which are formulated to maximize fluid and electrolyte absorption in the gut. They are a life-saving tool, especially for children and the elderly, where rapid rehydration is critical. While most healthy adults with mild dehydration can manage with water, ORS offers a significant advantage when battling illness-induced fluid loss.

Comparing popular hydrating beverages


Drink	Key Hydration Elements	Best For	Caveats
Water	H2O	Daily hydration, mild exercise	Lacks electrolytes for significant sweat loss
Milk	Electrolytes (Na, K, Ca), Carbs, Protein, Fat	Post-workout recovery, longer-lasting hydration	Not ideal for those with lactose intolerance or immediate rehydration needs
Oral Rehydration Solution (ORS)	Electrolytes (high sodium), Glucose	Illness-induced dehydration (diarrhea, vomiting)	Not necessary for casual hydration; specific formulation for illness
Coconut Water	Electrolytes (high Potassium), natural sugar	Replenishing potassium, light activity	Lower in sodium than sports drinks; not more hydrating than water for regular activity
Sports Drinks	Electrolytes (sodium, potassium), Carbs	High-intensity, long-duration exercise	High in added sugar and calories; not recommended for casual hydration
Herbal Tea	Water, various plant compounds	Flavorful, low-calorie hydration alternative	Most herbal teas do not contain significant electrolytes

Other effective hydrating drinks

Other options also stand out for their hydrating properties. Coconut water, for instance, is naturally rich in potassium and is a great alternative for replenishing electrolytes after lighter physical activity. However, it generally has a lower sodium content compared to sports drinks and is not superior to water for basic hydration. Herbal teas, like peppermint or chamomile, are caffeine-free and essentially flavored water, offering a pleasant and low-calorie way to increase fluid intake. Broth-based soups are another excellent choice, especially when sick, as they provide high water content and sodium, which helps with fluid retention. The presence of sodium in broth encourages the body to hold onto water, rather than simply passing it through.

The role of thirst

It's important to remember that for most individuals and moderate activity levels, plain water is perfectly sufficient. The body's thirst mechanism is a reliable indicator that you need to drink. Only when fluid loss is significant, such as during intense, prolonged exercise or illness, do the additional components of other beverages offer a distinct advantage. Even with superior hydrating options, overhydration can be dangerous, leading to a condition called hyponatremia (low sodium levels), especially for endurance athletes. The key is a balanced approach based on your specific needs.

Conclusion

While water is and will always be essential for life, it is not always the most hydrating beverage in every circumstance. Drinks containing a strategic combination of electrolytes, carbohydrates, protein, or fat—like milk, oral rehydration solutions, and certain sports drinks—can offer longer-lasting or faster rehydration when the body needs it most. For daily, casual hydration, sticking with plain water is the most accessible and healthiest choice. However, understanding the science behind the Beverage Hydration Index allows for more informed choices when faced with demanding physical activity or illness.

Learn more about the study on the Beverage Hydration Index (BHI) in the American Journal of Clinical Nutrition

Frequently Asked Questions

Scientific studies, including one from Scotland's St. Andrews University, have shown that milk and oral rehydration solutions hydrate better and for longer periods than plain water due to their specific composition of electrolytes, carbohydrates, fats, and proteins.

Milk is more hydrating because it contains natural sugars (lactose), protein, and fat that slow the rate of fluid absorption and gastric emptying. It also contains sodium, which helps the body retain fluid and minimizes urine output.

For most people and moderate exercise, water is sufficient. Sports drinks can be more beneficial than water during high-intensity or prolonged exercise (over 60 minutes) to replace significant fluid, electrolyte, and carbohydrate losses.

Coconut water is not significantly more hydrating than plain water for basic hydration. While it is rich in potassium and can help replenish electrolytes after light activity, it has lower sodium levels than many sports drinks and is not superior to water for regular hydration.

Yes, in moderation. The diuretic effect of caffeine is mild and temporary. Most research suggests that coffee and tea, when consumed in typical amounts, contribute positively to daily fluid intake and are about as hydrating as water.

You should use an Oral Rehydration Solution (ORS) over water when experiencing significant fluid loss due to illness, such as diarrhea or vomiting. The precise balance of glucose and electrolytes in ORS is medically formulated to promote rapid absorption and prevent dangerous dehydration.

Eating water-rich fruits and vegetables, like watermelon or cucumber, can contribute to your overall fluid intake, but they do not replace the need for drinking water. Approximately 20% of your daily fluid intake typically comes from the foods you eat.