Can You Use Milk to Rehydrate? The Surprising Hydration Benefits of Dairy

January 7, 2026 •

4 min read

According to a 2007 study published in the British Journal of Nutrition, milk proved to be a more effective post-exercise rehydration drink than both water and a standard sports drink. This surprising finding raises the question: can you use milk to rehydrate effectively in other situations beyond just recovering from a workout?

Quick Summary

This article explores why milk is an effective rehydrator, explaining the role of electrolytes, protein, and carbohydrates in fluid retention. It compares milk to other beverages, addresses different types of dehydration, and discusses when milk is the best choice for fluid replacement.

Key Points

Superior Fluid Retention: Studies show milk's electrolytes, protein, and carbohydrates promote better and longer-lasting fluid retention compared to water or many sports drinks.
Post-Exercise Recovery: Milk is an excellent post-workout beverage because its unique nutrient profile aids in replenishing fluids, repairing muscles, and restoring energy stores.
Electrolyte Replenishment: The natural sodium and potassium in milk are crucial for replacing minerals lost through sweat, which helps regulate the body's fluid balance.
Slowed Digestion: The presence of protein and carbohydrates slows down digestion, allowing for a more gradual and complete absorption of fluid into the body.
Daily Hydration Context: While highly effective for specific needs like recovery, plain water remains the best, calorie-free option for general daily hydration.

The Science Behind Milk's Hydration Power

While water is the body's primary fluid source, its ability to rehydrate efficiently is limited by its lack of electrolytes and macronutrients. Milk, however, contains a perfect trifecta of elements that makes it surprisingly effective for fluid replacement.

The Role of Electrolytes and Nutrients

Milk contains essential electrolytes like sodium and potassium, which are crucial for maintaining fluid balance in the body. When you sweat, you lose more than just water; you also lose these vital minerals. Rehydrating with milk helps to replenish these lost electrolytes, preventing your kidneys from flushing out excess fluid too quickly. Sodium, in particular, acts like a sponge, helping your body hold onto water and reducing urine output.

The Impact of Protein and Carbohydrates

Beyond electrolytes, milk contains protein and carbohydrates. The presence of protein and carbohydrates (lactose) slows down the rate of gastric emptying, meaning the fluid stays in your stomach for a longer period. This prolonged digestion allows for a more gradual and sustained absorption of fluid and nutrients into the bloodstream, leading to better overall fluid retention. In contrast, plain water is absorbed quickly, leading to faster urination and less efficient rehydration in scenarios of significant fluid loss. The carbohydrates in milk also aid fluid absorption by creating an osmotic gradient that helps move water from the intestine into the body.

Milk vs. Sports Drinks and Water

Research has shown that milk, particularly lower-fat varieties, can outperform water and sports drinks in certain rehydration scenarios. A landmark 2007 study found that participants who rehydrated with milk after exercise retained more fluid and produced less urine over a five-hour recovery period than those who drank water or a sports drink. A subsequent 2016 study, analyzing 13 different beverages, also found that milk offered better fluid retention than water.

A Comparative Look at Rehydration Beverages


Feature	Milk (Skim/Low-Fat)	Sports Drink	Plain Water
Electrolytes	High (Sodium, Potassium, Calcium)	Moderate (Sodium, Potassium)	None
Carbohydrates	Moderate (Lactose)	High (Added Sugar/Dextrose)	None
Protein	High-Quality (Casein & Whey)	None	None
Hydration Mechanism	Sustained release due to digestion	Rapid absorption	Rapid absorption, fast urination
Best For...	Post-exercise recovery, mild dehydration	High-intensity endurance exercise	General daily hydration
Calorie Content	Moderate	Varies, can be high	Zero

The Recovery Angle

For athletes, milk's benefits extend beyond just hydration. The combination of complete protein and carbohydrates not only helps restore glycogen stores but also aids in muscle repair and growth after strenuous activity. Chocolate milk, with its higher carbohydrate content, is an especially potent recovery drink. Sports drinks, while effective for immediate replenishment during high-intensity exercise, lack the protein content that supports long-term muscle recovery.

When to Use Milk for Rehydration

Milk is an excellent choice for rehydration in several specific situations. It is particularly effective after moderate to intense exercise where both fluid and nutrient losses need to be addressed. It is also beneficial for combating mild dehydration caused by illness or general fluid loss throughout the day, providing calories and nutrients that plain water lacks. For children or older adults who might not consume enough fluids and calories, milk can offer a robust hydration and nutritional boost.

Practical Tips for Using Milk as a Rehydrator

Post-Workout: A glass of low-fat or chocolate milk within 30-60 minutes after exercise can accelerate recovery by replacing fluids, electrolytes, and nutrients for muscle repair.
After Illness: Following a mild stomach bug or illness that caused fluid loss, milk can help restore fluid balance and provide much-needed calories and nutrients.
Between Meals: Adding a glass of milk to your day can be a simple way to maintain hydration and nutrient intake, especially for those with low calorie needs or poor appetite.

Important Considerations and When to Choose Water

While milk is a powerful rehydrator, it's not a replacement for water in all scenarios. For everyday hydration, especially during light activity, plain water remains the best, calorie-free option. Individuals with lactose intolerance or a dairy allergy should opt for other hydration sources, although lactose-free milk can be an alternative. In cases of severe dehydration, medical attention is required, and oral rehydration solutions are typically recommended. High-sugar beverages like soda or juice should be avoided, as their high sugar concentration can draw water from the body into the intestine, exacerbating dehydration.

The Verdict on Using Milk to Rehydrate

Ultimately, the question of whether you can use milk to rehydrate has a clear answer: yes, and in some situations, it's more effective than water alone. The combination of electrolytes, protein, and carbohydrates in milk works synergistically to promote better fluid retention and overall recovery, making it a powerful tool for rehydration after exercise or during periods of mild dehydration. However, plain water remains the optimal choice for general daily hydration, and milk is not a substitute for professional medical care in severe cases of dehydration.

Milk is more effective than water for prolonged hydration because its nutritional content slows gastric emptying and improves fluid retention.
Electrolytes like sodium and potassium in milk help the body hold onto fluids more efficiently.
Protein and carbs in milk support muscle recovery and sustained energy after exercise, making it an excellent recovery drink.
For most daily hydration needs, water is the best choice due to its lack of calories and simple, direct hydration.
Individuals with lactose intolerance should use caution and consider lactose-free or alternative hydration options.
In severe dehydration, milk is not a substitute for medical treatment.

Frequently Asked Questions

Yes, for post-exercise rehydration, milk is often more effective than plain water. The combination of water, electrolytes, and macronutrients in milk leads to better fluid retention and aids in muscle recovery, which plain water lacks.

People with lactose intolerance should avoid regular dairy milk for rehydration. However, lactose-free milk is a viable alternative that offers similar hydration benefits without causing digestive discomfort.

Yes, milk can help with mild dehydration from illness. Its nutrients and calories are beneficial when appetite is low, and its electrolyte content helps restore fluid balance more effectively than water alone.

Skim or low-fat milk is often cited as the most hydrating type of milk, potentially because its lower fat content results in faster gastric emptying compared to whole milk. However, both skim and whole milk have been shown to be effective.

Yes, chocolate milk is particularly beneficial for post-exercise recovery. It provides a great balance of carbohydrates and protein, which helps replenish glycogen stores and repair muscles, in addition to its hydrating properties.

Plant-based milks typically have a different nutritional profile than cow's milk, often with lower levels of electrolytes and protein. While they contain water, they may not offer the same enhanced fluid retention benefits for rehydration.

No, it is not recommended to rely solely on milk for all daily fluid intake. While beneficial for specific situations, plain water should be your primary source of hydration throughout the day due to milk's caloric density.