Is there a drink that hydrates you more than water? The surprising science of superior hydration

October 11, 2025 •

5 min read

According to a study published in the American Journal of Clinical Nutrition, some beverages can actually be more hydrating than plain water over a four-hour period due to their nutrient composition. So, is there a drink that hydrates you more than water? The answer hinges on the balance of electrolytes, protein, and carbohydrates, and understanding when to choose the right fluid for your needs.

Quick Summary

Milk and oral rehydration solutions offer longer-lasting hydration than water by slowing gastric emptying and aiding fluid retention through electrolytes and macronutrients. Plain water remains ideal for daily needs, while high-intensity exercise or illness may require more specialized drinks.

Key Points

Milk Hydrates More Than Water: Studies show that milk's combination of electrolytes, protein, fat, and lactose can lead to superior fluid retention compared to plain water.
Electrolytes are Key: Drinks containing electrolytes like sodium and potassium aid the body in absorbing and retaining fluid more effectively, particularly after significant fluid loss from sweating or illness.
Context is Everything: While water is best for daily, casual hydration, specific situations like post-intense exercise or recovery from sickness warrant more specialized, nutrient-dense fluids.
Sugar's Double-Edged Sword: In moderation, sugar (carbohydrates) can aid fluid absorption, but high sugar concentration in drinks like soda can be counterproductive, pulling water into the intestine.
Homemade Alternatives Exist: You can easily create effective and healthy electrolyte drinks at home using ingredients like water, juice, and a pinch of salt.
The BHI Provides a Guide: The Beverage Hydration Index (BHI) is a scientific measure that confirms some beverages, notably milk and ORS, have a greater short-term fluid retention capacity than water.

Understanding the Beverage Hydration Index (BHI)

For years, water has been crowned the king of hydration, and for good reason. It is calorie-free, universally available, and essential for human life. However, a 2016 study from Scotland's St. Andrews University introduced the Beverage Hydration Index (BHI) to measure how well and how long a beverage hydrates the body. The researchers found that some common drinks actually scored higher on the BHI than plain water. This surprising result doesn't mean you should abandon your daily water intake, but it does highlight the nuances of fluid absorption and retention in the body.

The science behind superior hydration

What makes certain beverages more hydrating than water? It comes down to their nutritional content, which affects how the body processes and retains the fluid.

The crucial role of electrolytes

Electrolytes are minerals, such as sodium, potassium, and magnesium, that have an electrical charge and are vital for numerous bodily functions, including maintaining fluid balance. When you sweat heavily, you lose more than just water; you lose electrolytes. Drinks containing these minerals, like milk and oral rehydration solutions, help replenish both fluid and lost salts. Sodium, in particular, acts like a sponge, helping the body hold onto water and resulting in less urine production. Drinking plain water alone after significant electrolyte loss can dilute the remaining electrolytes in your blood, which is not ideal for optimal fluid balance.

The impact of macronutrients

Macronutrients like protein, fat, and carbohydrates also play a significant role. These components slow down the rate at which fluid empties from the stomach. This slower gastric emptying allows for a more gradual and sustained hydration process, rather than the rapid absorption and subsequent excretion that can happen with plain water. This is a key reason why milk, which contains a blend of fats, proteins, and the sugar lactose, was found to be highly effective on the BHI. For athletes, this slow and steady release of fluid can be particularly beneficial for long-lasting performance and recovery.

A deeper look at the most hydrating beverages

Based on the BHI, here are some of the top-performing drinks for hydration:

Skim and Whole Milk: Topping the list, milk is an excellent rehydrator due to its balanced combination of electrolytes, natural sugars, protein, and fat. The protein and fat slow down digestion, leading to prolonged fluid retention. It's particularly effective for post-workout recovery, offering both hydration and nutrients for muscle repair.
Oral Rehydration Solutions (ORS): Formulated to combat dehydration from illness like diarrhea or vomiting, ORS drinks contain a specific ratio of glucose and electrolytes to maximize fluid absorption in the intestines. They are superior to water in medical situations requiring rapid and efficient rehydration.
Coconut Water: Popular for its natural electrolyte content, particularly potassium, coconut water is a refreshing and hydrating option, especially for light exercise. However, it generally contains less sodium than is needed for intense workouts with heavy sweating.
Fruit and Vegetable Juices: While juices are mostly water, their high sugar content can sometimes be counterproductive. High concentrations of sugar can trigger osmosis, drawing water out of the body and into the small intestine to dilute it. However, diluted 100% fruit juice can be a good source of hydration, especially combined with food.

What about common everyday drinks?

Coffee and Tea: The diuretic effect of caffeine has long been exaggerated. For moderate consumers, a cup of coffee or tea is as hydrating as water. Research shows the diuretic effect is only significant with high doses (over 300mg of caffeine) and is more likely to affect non-regular consumers. Adding milk to your coffee or choosing herbal teas can offset any mild diuretic effect.
Sports Drinks: For intense, prolonged exercise (over 60 minutes), sports drinks provide electrolytes and carbohydrates to replenish lost stores and fuel muscles. For everyday hydration or short workouts, they are often unnecessary and can contribute excess sugar and calories.
Alcohol: Acting as a diuretic, alcohol removes water from your tissues, leading to dehydration. While drinking a beer contains more fluid than a straight shot of whiskey, any alcohol consumption will require more water to replace the lost fluid.

Comparison of common beverages


Beverage	Key Hydrating Factors	Best For...	Hydration Index (vs. Water)
Skim Milk	Water, electrolytes, protein, carbohydrates	Post-workout recovery, general hydration (in moderation)	Significantly higher (1.58)
Oral Rehydration Solution	Water, electrolytes (sodium, potassium), glucose	Illness (diarrhea/vomiting), rapid rehydration	Significantly higher (1.54)
Whole Milk	Water, electrolytes, protein, fat, carbohydrates	Post-workout recovery, general hydration (in moderation)	Significantly higher (1.50)
Still Water	Pure H₂O, no calories or additives	Everyday hydration, workouts under 60 minutes	1.0 (baseline)
Sparkling Water	Pure H₂O, some minerals	Everyday hydration, light exercise	No significant difference (1.0)
Sports Drink	Water, carbohydrates, electrolytes (varied amounts)	Intense exercise over 60 minutes	No significant difference (1.09)
Coffee / Tea (moderate)	Water, some antioxidants	Everyday fluid intake (in moderation)	No significant difference (1.0)
Fruit Juice	Water, carbohydrates, vitamins	Supplemental hydration (limited intake)	Slightly higher initially, no long-term difference

DIY homemade electrolyte drink

For those who prefer a natural, low-sugar alternative to commercial sports drinks, making your own electrolyte beverage is a simple process.

Ingredients:

2 cups water or coconut water
1/2 cup 100% fruit juice (like orange or lemon)
1/4 teaspoon sea salt
1-2 tablespoons honey or maple syrup (optional, for energy and taste)

Instructions: Combine all ingredients and mix thoroughly until the salt and sweetener (if using) are fully dissolved. This mixture provides a balance of water, electrolytes, and quick energy, making it an ideal recovery drink after a strenuous activity.

Conclusion: Choosing the right fluid for the right time

While plain water remains the gold standard for daily hydration needs, the answer to the question, is there a drink that hydrates you more than water?, is a qualified yes. For specific scenarios like intense exercise, significant fluid loss due to illness, or for groups like children and the elderly, beverages containing a combination of water, electrolytes, carbohydrates, and protein offer a more efficient and longer-lasting hydration effect. Understanding the science behind the Beverage Hydration Index allows you to make more informed choices to optimize your hydration strategy, ensuring you get the most out of every drink.

For more detailed nutritional information, you can consult resources like The American Journal of Clinical Nutrition.

Best and worst hydrating drinks: At a glance

Best: Water, skim/whole milk, oral rehydration solutions, coconut water, diluted fruit juices, broth-based soups, herbal tea.
Worst: Highly sugary beverages like sodas and undiluted juices, energy drinks with high caffeine and sugar, alcoholic beverages.

When to choose something other than water

After intense, prolonged exercise: Opt for milk or a sports drink to replenish glycogen and electrolytes.
During bouts of illness: Use an oral rehydration solution to effectively restore lost fluids and electrolytes, especially with diarrhea or vomiting.
To maintain hydration over time: A glass of milk can keep you feeling hydrated longer than plain water, useful for prolonged periods without drinking opportunities.

Frequently Asked Questions

Studies have shown that both skim and whole milk are more hydrating than water over a four-hour period. Skim milk performed slightly better on the Beverage Hydration Index, but both are effective options for sustained hydration.

Yes, ORS are specifically formulated with an optimal balance of electrolytes and glucose to facilitate rapid and efficient fluid absorption, making them superior to plain water for rehydration during illness like diarrhea or vomiting.

For low-intensity or short-duration activities, water is sufficient. For high-intensity, prolonged exercise (over 60 minutes), sports drinks provide necessary electrolytes and carbohydrates to replenish energy and fluids lost through sweat.

In moderate amounts (2-4 cups daily), the diuretic effect of caffeine is minimal, and coffee contributes to your daily fluid intake similarly to water. Excessive consumption, however, can lead to fluid loss.

Some sugar can aid in fluid absorption. However, high sugar concentrations, such as those found in sodas and some juices, can draw water from the body into the intestine through osmosis, making them less hydrating.

Yes, you can make a simple electrolyte drink by mixing water, a pinch of salt, a small amount of juice, and an optional sweetener like honey. This is a healthier alternative to many store-bought options.

For most everyday circumstances, water remains the best choice for hydration. It is calorie-free, essential for bodily functions, and effective for rehydrating during normal activities.