Can the Body Get Water from Milk? The Surprising Hydration Facts

December 26, 2025 •

3 min read

Milk is composed of roughly 87-90% water, meaning your body can certainly get water from milk. Due to its unique composition of protein, lactose, and electrolytes, recent studies show that milk can actually be more hydrating than plain water for longer periods.

Quick Summary

Milk is an effective hydration source due to its high water content, electrolytes, and other nutrients that promote better fluid retention. It can be a superior rehydration choice after exercise, but water remains the best daily choice.

Key Points

High Water Content: Milk is comprised of 87-90% water, making it a direct source of fluid for the body.
Superior Hydration Post-Exercise: Studies show that milk's combination of nutrients makes it more effective than water or sports drinks for rehydration after exercise, promoting longer fluid retention.
Electrolytes are Key: The electrolytes in milk, such as sodium and potassium, are essential for regulating fluid balance and helping the body retain water.
Slows Digestion: Proteins and natural sugars in milk slow gastric emptying, which leads to a slower, more sustained release of fluid into the bloodstream compared to water.
Water is Still King for Daily Needs: Despite milk's advantages, water is the best and lowest-calorie option for meeting daily hydration requirements for most people.
Consider Calorie and Intolerance: The calorie content of milk and potential for lactose intolerance are factors to consider, especially when relying on it for hydration.

Understanding Hydration: Beyond Plain Water

Hydration is influenced by more than just a beverage's water content. While water is absorbed quickly, it also leaves the body rapidly. Beverages containing electrolytes, proteins, and carbohydrates can improve fluid retention by slowing gastric emptying and aiding absorption into the bloodstream. Milk's composition makes it surprisingly effective; its nutrients help the body retain fluid longer, making it superior to plain water and some sports drinks for rehydration in certain studies.

The Nutritional Components That Make Milk Hydrating

Key components in milk contribute to its hydrating properties:

High Water Content: Milk is a direct fluid source, with whole milk around 88% water and skim milk closer to 91%.
Essential Electrolytes: As a natural source of electrolytes like sodium and potassium, milk helps maintain fluid balance, with sodium particularly important for water retention.
Protein and Carbohydrates: Protein and lactose slow stomach emptying, leading to sustained fluid release and absorption.
Balanced Osmolality: Milk's composition supports optimal fluid absorption, aiding efficient rehydration, especially after sweating.

Milk vs. Water vs. Sugary Drinks: A Comparison

Different drinks have varying hydrating effects. A 2016 study in The American Journal of Clinical Nutrition found skim and whole milk more hydrating than water due to better fluid retention from milk's nutrients.

How Different Beverages Affect Hydration


Feature	Plain Water	Milk	Sugary Drinks (Soda, Juice)
Water Content	100%	~87-91%	Varies, but often high
Electrolytes	Trace minerals (varies by source)	Sodium, Potassium, Calcium	Generally low, or artificially added
Carbohydrates	None	Natural lactose	Concentrated added sugars
Protein/Fat	None	Yes	None
Digestion Speed	Rapid	Slower due to protein/fat	Can be rapid, but high sugar can disrupt balance
Fluid Retention	Good for immediate rehydration, but fluid is lost quickly	Very good for sustained hydration over time	Poor; high sugar can cause water to be pulled into the intestine
Best Use	Daily fluid intake	Post-exercise rehydration; nutrient-rich source	Limited; not recommended for hydration

When is Milk Most Beneficial for Hydration?

While water is sufficient for most daily needs, milk is effective in specific situations:

Post-Exercise Recovery: Milk is an ideal recovery drink after intense workouts due to its fluid, electrolytes, protein, and carbohydrates, often outperforming water or typical sports drinks. Chocolate milk also helps replenish muscle glycogen.
During Illness: For mild dehydration, milk's electrolytes can help, but if not tolerated, water or oral rehydration solutions are better.

Considerations and Precautions

Milk is not a universal hydration solution:

Calories: Milk contains calories, so relying solely on it for hydration can increase caloric intake, impacting weight management.
Lactose Intolerance: Those with lactose intolerance need alternatives like lactose-free milk or water.
Daily Hydration: Meeting recommended daily fluid intake (around 3.7 liters for men, 2.7 for women) solely with milk is impractical and not advised. Water is the best and most affordable choice for everyday hydration.

Conclusion

Yes, the body can get water from milk. Its high water content and nutritional profile, including electrolytes, proteins, and carbohydrates, make it a highly effective hydrating beverage. Milk can even be superior to water for post-exercise rehydration due to promoting longer fluid retention. However, plain water remains the most practical choice for everyday hydration. For those without lactose intolerance, incorporating milk can boost hydration and nutrient intake, but it shouldn't replace water as the primary fluid source.

For more information on nutrition and health, consider exploring resources from reputable institutions such as the Harvard T.H. Chan School of Public Health: https://www.hsph.harvard.edu/nutritionsource/milk/.

Frequently Asked Questions

Yes, milk is a very effective source of hydration. It is composed of a high percentage of water, along with key nutrients like electrolytes, proteins, and carbohydrates that help the body retain fluid for longer periods.

For immediate hydration, plain water is very efficient. However, for sustained hydration, studies have shown milk can be more effective than water. This is because its nutrients slow digestion and aid fluid retention, resulting in less urine production.

Milk is hydrating because it contains a natural blend of water, electrolytes (sodium and potassium), and macronutrients (protein, fat, and lactose). This combination slows the rate of fluid absorption and retention in the body.

No, milk cannot replace water as your sole source of hydration. Water is calorie-free and the best option for meeting your regular daily fluid needs. Milk is a great supplement, especially after exercise, but it contains calories and should not be your only hydrating beverage.

Yes, milk is an excellent post-workout recovery drink. It provides the fluid and electrolytes needed for rehydration, along with high-quality protein for muscle repair and carbohydrates to replenish energy stores.

Skim milk is slightly more hydrating than whole milk because it has a higher water content and lower fat percentage. Both are effective, but skim milk provides more fluid per volume.

Milk is often comparable to, and in some cases more effective than, traditional sports drinks for rehydration. Milk contains natural electrolytes and a balance of protein and carbs that help the body retain fluid better than many commercial sports drinks.