Does Milk Actually Hydrate You More Than Water?

November 17, 2025 •

3 min read

According to a 2016 study published in the American Journal of Clinical Nutrition, both whole and skim milk were found to be more hydrating than plain water, largely due to their electrolyte, protein, and carbohydrate content. So, does milk actually hydrate you more than water? The answer is more complex than a simple 'yes' or 'no' and depends heavily on the specific context and your body's needs.

Quick Summary

Milk can be more hydrating than water in specific situations, primarily because its nutrients promote longer-lasting fluid retention compared to plain water, though it's not a substitute for daily H2O intake.

Key Points

Sustained Hydration: Milk's electrolytes, protein, and fat slow down fluid absorption, allowing the body to retain fluids longer than it would with plain water.
Electrolyte Replenishment: The sodium and potassium in milk help the body effectively replace electrolytes lost through sweat, making it ideal for post-exercise recovery.
Not an Everyday Substitute: Due to its caloric content, milk should not replace water for general daily hydration, especially for those on a calorie-controlled diet.
Optimal for Recovery: Milk is particularly effective for rehydration after intense exercise, offering a balanced mix of fluids, carbs, and protein for muscle repair.
Plant-Based Alternatives Differ: Plant-based milks lack the same nutritional profile as cow's milk and therefore do not provide the same sustained hydrating effects.
Context is Key: Choosing between milk and water depends on the situation—water is best for routine hydration, while milk is superior for sustained fluid retention after exertion or mild dehydration.

The Science Behind Milk's Superior Hydration

While water is the undisputed king for everyday fluid needs, research has shown that milk can outperform it in certain scenarios. The secret lies in milk's unique nutritional makeup, which includes a balanced combination of electrolytes, macronutrients, and water itself.

How Milk's Composition Enhances Hydration

Electrolytes: Minerals like sodium and potassium, naturally found in milk, play a crucial role in maintaining fluid balance within the body. Sodium, in particular, acts like a sponge, helping the body hold onto water and reducing the frequency of urination. After sweating, replenishing these lost electrolytes is key to effective rehydration.
Macronutrients (Protein, Fat, and Carbs): Milk contains natural proteins, fats, and carbohydrates (lactose). These components slow down the rate at which fluid empties from the stomach. This slower gastric emptying allows for a more gradual and sustained absorption of the liquid, helping the body retain fluids for a longer period compared to drinking plain water, which is absorbed more quickly and can be excreted faster.
Balancing Osmolarity: The concentration of sugars and electrolytes in milk helps it achieve a balanced osmolarity, the measure of solute concentration. This balance helps regulate how water is absorbed into the cells, optimizing the hydration process and preventing excessive urination.

Milk vs. Water: A Comparison for Hydration

To understand the practical differences, consider the table below, which compares milk and water for various hydration needs.


Feature	Milk	Water
Best For	Post-exercise rehydration, replacing electrolytes, recovery from mild dehydration	All-day hydration, basic fluid needs, low-calorie option
Fluid Retention	High; prolonged due to protein, fat, and electrolytes	Lower; faster absorption and excretion
Nutrient Content	High in electrolytes, protein, carbs, and calories	Minimal to zero, depending on source
Gastric Emptying	Slowed by macronutrients, leading to sustained hydration	Fast; passes through the stomach quickly
Caloric Impact	High; contains calories that contribute to overall intake	Zero calories
Cost	More expensive than tap water	Free (tap water) or inexpensive

When to Choose Milk for Optimal Hydration

While milk has its benefits, it is not a daily replacement for water. Its higher calorie and nutrient density make it better suited for specific circumstances where replenishing more than just fluid is necessary. Here are some scenarios where milk shines as a hydration choice:

Post-Intense Exercise: After a strenuous workout that results in significant sweat loss, milk (especially chocolate milk) can be highly effective. The combination of water, electrolytes, protein, and carbohydrates helps to rehydrate the body, repair muscles, and replenish energy stores.
After Mild Dehydration: For instances of mild dehydration, such as during or after illness, milk can aid in restoring both fluid and essential nutrients more effectively than plain water alone.
Children and Elderly: In certain cases, milk can be a useful rehydrator for children and the elderly who may need to restore fluids and nutrients simultaneously. However, this should always be done under proper guidance.

The Role of Plant-Based Milks

With the rise in dairy-free diets, many wonder if plant-based alternatives offer the same hydrating benefits. Most plant-based milks, such as almond or oat milk, are primarily water and typically lack the same balance of electrolytes, protein, and fat found in dairy milk. While they contribute to overall hydration, they don't offer the same sustained fluid retention. Fortified soy milk, which can have a more comparable nutritional profile, is often the closest alternative, but checking the nutrition label is always recommended.

Conclusion: Finding the Right Hydration Balance

The science confirms that milk, particularly dairy milk, offers a unique composition that makes it more effective for sustained hydration than water in specific situations. The combination of electrolytes and macronutrients slows gastric emptying, helping the body retain fluids longer. However, this does not mean milk should replace water as your primary source of hydration. For day-to-day fluid intake, especially for low-calorie hydration, water remains the best and most accessible choice. The key is to understand your body's needs and choose the right beverage for the right time, whether it's a glass of water to quench your thirst or a recovery-focused glass of milk after a tough workout.

Learn more about the science of hydration from a leading authority by visiting the National Institutes of Health (NIH) website.

Frequently Asked Questions

No, water is the best choice for everyday hydration and low-calorie fluid needs. Milk is more effective for sustained hydration after intense exercise or when recovering from mild dehydration due to its added nutrients.

The protein, fat, and lactose in milk slow down gastric emptying, the rate at which fluid leaves your stomach. This allows for a more gradual absorption of fluid and electrolytes, preventing rapid urination and promoting sustained hydration.

Yes, chocolate milk is often recommended as an excellent post-workout recovery drink. It provides a balanced ratio of carbohydrates and protein to refuel muscles, plus electrolytes for effective rehydration.

Plant-based milks generally do not offer the same hydrating benefits as dairy milk. While they contain water, they lack the specific balance of electrolytes and macronutrients that slow absorption and aid fluid retention.

No, milk is hydrating, but excessive consumption can lead to digestive issues like bloating, especially for those with lactose intolerance. It's also high in calories, so moderation is key.

The electrolytes, particularly potassium and calcium, found in milk are important for proper muscle function. Replenishing these electrolytes after exercise can help prevent or alleviate muscle cramps related to dehydration.

Both skim and whole milk have been found to be very hydrating. Some studies show a slight advantage for skim milk, potentially due to its lower fat content, but both are superior to plain water for sustained fluid retention.