Is Skim Milk Good for Hydration? A Scientific Look at Dairy

January 4, 2026 •

3 min read

According to a study published in the American Journal of Clinical Nutrition, beverages containing milk were found to be more hydrating than plain water. This surprising finding has prompted many to question the long-held belief that water is the ultimate hydration source and ask: is skim milk good for hydration?

Quick Summary

This article explores the scientific evidence behind skim milk's hydrating properties, examining its nutrient composition and how it compares to water and sports drinks for rehydration, particularly after exercise.

Key Points

Superior to water for fluid retention: The natural electrolytes and macronutrients in skim milk cause slower gastric emptying, resulting in better fluid retention compared to plain water.
Excellent post-exercise recovery drink: Skim milk provides not only rehydration but also protein and carbohydrates needed to repair muscles and replenish energy stores after a workout.
Provides essential electrolytes: It is a natural source of vital electrolytes like sodium and potassium, which are crucial for maintaining proper fluid balance.
Helps reduce muscle soreness: Some research indicates that consuming milk after resistance training can help reduce exercise-induced muscle damage and soreness.
Best for strategic rehydration: While water is best for general daily needs, skim milk is an effective choice for strategic rehydration when you also need to replenish nutrients.
Contains fewer calories than whole milk: Skim milk offers the hydrating benefits of milk with a lower calorie count compared to its full-fat counterpart.

The Science Behind Skim Milk and Hydration

Skim milk's composition of electrolytes, proteins, and carbohydrates makes it effective at promoting fluid retention. Unlike water, which is absorbed quickly, milk's macronutrients slow gastric emptying, allowing the body to absorb fluids and electrolytes more gradually and efficiently.

The Role of Electrolytes

Electrolytes like sodium, potassium, calcium, and magnesium are crucial for fluid balance. Milk is a natural source of these, helping the body retain water, especially after loss through sweat. Water lacks these electrolytes and is absorbed and excreted faster.

Protein and Carbohydrates: The Hydration Duo

The protein and carbohydrates (lactose) in skim milk contribute to its hydrating effect. They prolong fluid absorption in the small intestine, reducing urine output and improving fluid retention. This makes skim milk beneficial for post-exercise recovery, replenishing fluids and providing nutrients for muscle repair.

Skim Milk vs. Water vs. Sports Drinks

While water is the standard for daily hydration, skim milk is a strong option after moderate-to-intense exercise. The following table compares these beverages:


Feature	Skim Milk	Plain Water	Sports Drinks
Primary Hydrating Mechanism	Electrolytes, protein, carbs (slow absorption)	Rapid water intake	Added electrolytes and sugars (moderate absorption)
Electrolytes	Natural source of sodium, potassium, etc.	Lacks electrolytes	Typically added sodium and potassium
Macronutrients	Contains protein and lactose (carbs)	None	Contains sugar (carbs)
Gastric Emptying	Slower, promoting longer fluid retention	Fastest	Moderate, depending on sugar concentration
Best Use Case	Post-exercise rehydration and recovery	General, daily hydration	During prolonged, intense endurance exercise

The Beverage Hydration Index

A 2016 study developed a Beverage Hydration Index (BHI) to rank drinks based on fluid retention. Skim milk ranked highly, surpassing some oral rehydration solutions, due to its balance of water, nutrients, and electrolytes.

Potential Drawbacks and Considerations

Skim milk's hydrating benefits are clear, but it's not universally suitable. Individuals with lactose intolerance or milk protein allergies should avoid it. Its calorie content also means it's not ideal for all-day hydration or weight management if consumed excessively. Water remains the best choice for general daily hydration without added calories. Skim milk is best used strategically after activity.

How to Incorporate Skim Milk for Hydration

To use skim milk for hydration effectively:

Post-Workout: Drink a glass or have cereal with skim milk after exercise to replenish fluids and aid muscle recovery.
After Illness: During mild illness with fluid loss, skim milk can help restore electrolytes and fluid balance.
Balanced Approach: Include skim milk as part of a nutritious diet, but ensure adequate daily water intake for overall hydration.

Conclusion

So, is skim milk good for hydration? Yes, particularly for rehydration beyond just replacing fluids. Its combination of water, electrolytes, protein, and carbohydrates helps the body retain fluids more effectively than water. While water is ideal for daily hydration, skim milk is a natural and effective option for post-exercise or when nutrient replenishment is also needed, offering a good alternative to sports drinks. For specific study details, refer to the National Institutes of Health.

Key Takeaways:

Skim milk is more hydrating than water in some cases: Electrolytes, protein, and carbohydrates promote longer fluid retention.
Ideal for post-workout recovery: Replenishes fluids and provides nutrients for muscle repair.
Contains valuable electrolytes: Provides natural sodium and potassium for fluid balance.
Protein and carbs slow absorption: Leads to better long-term fluid retention.
Water is still the daily standard: Best for general daily hydration due to zero calories.

Resources

Shirreffs, S. M., Watson, P., & Maughan, R. J. (2007). Milk as an effective post-exercise rehydration drink. British Journal of Nutrition.
Maughan, R. J., et al. (2016). A randomized trial to assess the potential of different beverages to affect hydration status: Development of a beverage hydration index. American Journal of Clinical Nutrition.
Healthline. (2021). Is Milk Good for Dehydration?
Vogue. (2025). The Surprising Drink That's More Hydrating Than Water.
Everyday Health. (2022). Does Milk Count as Fluid?

Frequently Asked Questions

Yes, several studies indicate that skim milk can be more hydrating than plain water due to its electrolytes, proteins, and carbohydrates, which help the body retain fluids for a longer period.

The best time to drink skim milk for hydration is after moderate-to-intense exercise, when you need to replace lost fluids, electrolytes, and nutrients for muscle recovery.

No, it is not recommended to replace all water consumption with skim milk. Water is the best source for daily hydration due to its lack of calories, while skim milk should be used strategically, such as for post-workout rehydration.

Skim milk is hydrating due to its composition of approximately 90% water, along with natural electrolytes (sodium, potassium) and macronutrients (protein and lactose) that slow down absorption and improve fluid retention.

For mild dehydration, especially when fluids and electrolytes are lost through illness, milk can be a suitable option for rehydration. However, in severe cases, medical attention is needed.

Yes, some studies suggest that skim milk can be a more effective and natural post-exercise rehydration drink than commercial sports drinks, providing superior fluid retention and additional nutrients.

For individuals with lactose intolerance, consuming milk can cause digestive issues that could hinder hydration. Lactose-free milk or water would be better choices in this case.