What is the most hydrating beverage to drink?

November 29, 2025 •

4 min read

According to a 2015 study published in the American Journal of Clinical Nutrition, plain water is not the most hydrating beverage for long-term fluid retention. The study found that drinks containing electrolytes, fats, and protein, like milk and oral rehydration solutions, can keep you hydrated for longer. This raises the question: what is the most hydrating beverage to drink for optimal fluid balance?

Quick Summary

This article explores the science behind hydration, examining the beverage hydration index (BHI) and identifying which drinks offer the best fluid retention. It compares popular options like water, milk, and sports drinks to help determine the best choices for daily hydration versus post-exercise recovery.

Key Points

Milk Is Highly Hydrating: Studies show that skim milk and whole milk are more effective for long-term hydration than water due to their protein, fat, sugar, and electrolyte content.
ORS for Severe Dehydration: Oral Rehydration Solutions (ORS) are scientifically formulated with electrolytes and glucose to maximize fluid retention and are most effective for illness-induced dehydration.
Water is Best for Daily Needs: For general, day-to-day hydration without intense activity, plain water is the ideal, calorie-free choice.
Sports Drinks Contain Added Sugar: While beneficial for prolonged, intense workouts, many commercial sports drinks contain high amounts of added sugar and artificial ingredients.
Electrolytes are Key for Retention: Drinks with electrolytes like sodium and potassium aid the body in holding onto water, slowing urine output and promoting more efficient rehydration.
Consider Natural Alternatives: Coconut water is a natural, potassium-rich electrolyte source, and herbal teas offer caffeine-free hydration with added flavor.
Context Matters for Your Choice: The best beverage depends on the situation—use water for daily needs, and richer options like milk or ORS for recovery after heavy fluid loss.

The Science of Hydration: Beyond Just Water

For years, water has been considered the undisputed champion of hydration. While it is essential for life and perfect for daily needs, research has revealed that other beverages can be more effective for maintaining hydration for longer periods. This is thanks to factors that influence how quickly fluids leave the stomach and how well the body retains them. The "Beverage Hydration Index" (BHI), developed in a 2015 study by researchers at Scotland's St. Andrews University, provides a valuable comparison. The study found that beverages with nutrients like protein, fat, and electrolytes often perform better than plain water over a four-hour period.

The Role of Electrolytes, Carbohydrates, and Protein

What makes some drinks more hydrating? The presence of specific components is key. Electrolytes, such as sodium and potassium, are minerals that play a critical role in maintaining fluid balance. Sodium, in particular, acts like a sponge, helping the body hold onto water and resulting in less urine output. Carbohydrates and proteins can also slow down the gastric emptying process, meaning the liquid stays in the stomach longer and is absorbed more gradually over time, providing more sustained hydration. These elements are why certain drinks, like milk and oral rehydration solutions (ORS), consistently score higher on the BHI than plain water.

Top Contenders for the Most Hydrating Beverage

Skim Milk: A top contender on the BHI, skim milk is more hydrating than plain water due to its lactose (sugar), protein, and sodium content. This combination helps slow gastric emptying and improves fluid retention. It is an excellent choice for rehydration after exercise.
Oral Rehydration Solutions (ORS): These purpose-built solutions are designed to rehydrate effectively after significant fluid loss from sweating, vomiting, or diarrhea. Their specific balance of water, glucose, and electrolytes (sodium and potassium) maximizes fluid retention. Pedialyte is a common brand, but homemade versions also exist.
Coconut Water: Often marketed as "nature's sports drink," coconut water is naturally rich in electrolytes, particularly potassium. It is a refreshing and low-calorie option, although it typically contains less sodium than milk or commercial sports drinks. Adding a pinch of salt can improve its effectiveness for post-workout rehydration.
Fruit Juice: 100% fruit juice, especially watermelon juice, offers a high water content and natural vitamins. However, the high sugar concentration can pull water into the intestine, potentially hindering absorption, so it is best consumed in moderation or diluted.
Herbal Tea: For those seeking a warm, flavorful option, herbal teas (like chamomile or peppermint) are caffeine-free and contribute to your overall fluid intake. Like water, they are a solid choice for general, low-intensity hydration.

Comparison Table of Hydrating Beverages


Beverage	Key Hydrating Components	Best For...	Considerations
Skim Milk	Lactose, protein, sodium, fat	Post-exercise recovery, sustained hydration	Higher calories than water, not for lactose intolerance.
Oral Rehydration Solution (ORS)	Water, glucose, sodium, potassium	Replenishing significant fluid and electrolyte loss	Specific formula, can be high in sugar.
Coconut Water	Potassium, magnesium	Low-intensity exercise, general hydration	Lower in sodium; can be pricey.
Plain Water	Pure water	Everyday hydration needs	Lacks electrolytes for optimal fluid retention after intense loss.
Sports Drinks	Water, electrolytes, carbs	Intense or prolonged athletic activity	Often high in added sugar, artificial flavors.
Herbal Tea	Water, antioxidants	General hydration, relaxing alternative	Must be caffeine-free; not for high-intensity recovery.

Making the Best Hydration Choice for You

The right beverage depends on the situation. For daily, casual hydration, plain water is the gold standard and remains the healthiest choice due to its lack of calories and additives. It’s readily available and affordable. However, for specific scenarios, a different beverage might be more beneficial.

Following an intense workout, prolonged physical activity, or during illness causing fluid loss, opting for a drink with a more complete nutritional profile is wise. This is where options like skim milk or a professionally formulated ORS truly shine, providing the necessary electrolytes and other nutrients to restore your body’s fluid balance more effectively and for a longer duration. For moderate activity, coconut water or diluted 100% fruit juice can serve as a suitable compromise, offering electrolytes and flavor without excessive sugar.

Ultimately, understanding the properties that influence hydration beyond just water content allows you to make more informed decisions based on your body’s immediate needs. Listen to your body and choose the beverage that best supports your level of activity and overall health goals.

Conclusion

While water is the fundamental liquid for daily hydration, it is not always the most effective choice for sustained fluid retention after significant loss. Research shows that drinks containing a mix of water, electrolytes, and other nutrients like protein and fat—such as skim milk and oral rehydration solutions—are superior for promoting longer-lasting hydration. Making an informed choice based on your activity level and health status is key to maintaining optimal hydration. For routine needs, plain water is sufficient and healthy, but for faster or longer-lasting recovery, consider the boosted benefits of other beverages. A balanced approach ensures you are always well-hydrated for peak performance and overall wellness.

Sources

*** American Journal of Clinical Nutrition. The Beverage Hydration Index: Influence of Electrolytes, Carbohydrate and Protein*.
*** Times of India. Water isn't the most hydrating drink—here's what is*.
*** ClickOnDetroit. Study finds milk may hydrate better than water*.
*** Healthline. 8 Electrolytes Drinks to Add to Your Wellness Routine*.
*** WebMD. Dehydration Treatment: How to Rehydrate Fast*.
*** GoodRx. The Best Hydrating Drinks High in Electrolytes and Nutrients*.
*** Vogue. The Surprising Drink That's More Hydrating Than Water*.

Frequently Asked Questions

Yes, absolutely. Plain water is the gold standard for everyday hydration. It is calorie-free and essential for most bodily functions. However, research indicates that drinks with electrolytes and other nutrients may be better for fluid retention after significant fluid loss from intense activity or illness.

Milk is highly hydrating because it contains natural sugars (lactose), protein, fat, and electrolytes (including sodium). This combination slows down the rate at which fluid leaves your stomach and promotes better fluid retention in the body, which was confirmed by a 2015 study from St. Andrews University.

Sports drinks can be effective for rehydration during or after prolonged, intense exercise because they contain carbohydrates and electrolytes. However, they often contain high amounts of added sugar, which isn't necessary for light or moderate activity and can counteract healthy hydration goals.

An oral rehydration solution (ORS) is a medical-grade beverage specifically formulated with a precise balance of water, glucose, and electrolytes (sodium, potassium). It is designed to quickly and effectively replace fluids and minerals lost due to severe dehydration from conditions like vomiting or diarrhea.

Coconut water is a natural source of electrolytes, particularly potassium, making it a good choice for hydration during moderate activity. To improve its effectiveness for replacing sweat lost during intense exercise, adding a pinch of salt is recommended, as it is naturally low in sodium.

Moderate consumption of caffeinated drinks like coffee or tea contributes to daily fluid intake. However, high doses of caffeine can have a mild diuretic effect, causing increased urination. In moderation, they can be hydrating, especially if balanced with other fluids.

Yes, you can make an effective and natural hydrating drink at home. A simple recipe might involve combining water with a pinch of sea salt and some lemon or orange juice for electrolytes. Many resources online offer recipes for oral rehydration solutions using sugar and salt.