Yes, milk is very hydrating, often even more so than water, because it contains water, natural electrolytes (like sodium and potassium) to help your body retain fluid, and some carbohydrates (lactose) and protein that slow stomach emptying, leading to more sustained hydration. Studies show milk helps people produce less urine and retain more fluid compared to plain water or sports drinks, making it excellent for rehydration after exercise.
Short answer: Yes--milk hydrates and can count toward daily fluid needs, but it's not a one-to-one replacement for plain water for everyone because of calories, electrolytes, macronutrients, and situational factors. Milk is ~87--90% water, so it contributes substantially to daily fluid intake.
Short answer: No -- you should not replace plain water with milk as your sole fluid. Milk is nutritious but has calories, protein, fat, sugar (lactose), and can cause digestive or metabolic issues when consumed as the only or primary beverage.
For example, many fruits and vegetables, such as watermelon and spinach, are almost 100% water by weight. In addition, beverages such as milk, juice and herbal teas are composed mostly of water. Even caffeinated drinks — such as coffee and soda — can contribute to your daily water intake.
Milk is a natural source of fluid. Specifically, milk contains about 87% water, making it a natural choice for a hydrating drink. And remember, not only does dairy milk contain water naturally, but it also contains hydration-supporting electrolytes and sugars in the mix which will help you retain the water therein.
The most unhealthy drinks to keep you hydrated
According to one study, drinking lowfat or fat-free milk after exercising could restore hydration better than any other popular post-exercise beverages.
Research shows that milk is one of the best beverages for hydration, even better than water or sports drinks.
Milk is more hydrating than water
For example, milk was found to be even more hydrating than plain water because it contains the sugar lactose, some protein and some fat, all of which help to slow the emptying of fluid from the stomach and keep hydration happening over a longer period.
The "2-hour coffee rule" suggests waiting 90 minutes to 2 hours after waking up to drink your first cup of coffee to optimize caffeine's effects, avoid interfering with your natural cortisol spike (which peaks shortly after waking), and potentially prevent afternoon energy crashes. This timing allows caffeine to work better when cortisol levels naturally drop and adenosine (the chemical that makes you sleepy) builds up, leading to better focus and alertness later in the day, though individual experiences vary.
Gen Z isn't drinking as much milk due to health concerns (lactose intolerance, acne), ethical/environmental worries about dairy farming, the influence of social media promoting alternatives, increased awareness of dairy's downsides, and a desire for healthier, more personalized options like plant-based milks, though they still enjoy other dairy products like cheese and yogurt. They question traditional health advice and are swayed by peer culture and eco-consciousness, leading them toward alternatives for taste, values, and lifestyle fit.
The surprising finding was discovered via a study that compared hydration from different beverages by analyzing fluid retention levels in the hours after drinking. Shockingly, both whole cow's milk and skim milk were found to be among the most hydrating beverages—even surpassing mineral water in some conditions.
Milk is a great source of protein and nutrients like vitamin A, vitamin D, and calcium. Most people can drink traditional dairy milk every day. Milk offers numerous health benefits, such as promoting bone and muscle health, weight management, and skin health.
For most people, water is ideal for hydration. The lack of sugar and other additives makes it one of your best options. Other drinks can also help you stay hydrated. Some examples of hydrating drinks include coconut water, smoothies, and broth.
For everyday hydration, water is best, but for intense exercise or significant fluid loss, electrolyte drinks (like sports drinks or tablets) are superior for replenishing sodium and potassium; milk, coconut water, and even unsweetened tea/coffee also count, while natural options like chia seeds or 100% juice (in moderation) offer extra benefits. The "best" drink depends on your activity level, with plain water for normal days and electrolyte-rich drinks for strenuous activity or heat.
While milk has hydrating effects and tons of nutrients, drinking too much milk can have adverse effects. Excessive milk consumption can cause digestive issues like bloating, stomach discomfort, and diarrhea—especially for those with lactose intolerance.
Other drinks and foods can help you stay hydrated, but some may add extra calories from sugar to your diet. Drinks like fruit and vegetable juices, milk, and herbal teas can contribute to the amount of water you get each day.
Milk can help support fluid balance, though not in the same way as traditional hydration. Instead, it provides key nutrients that promote post-fitness recovery, including: Electrolytes (calcium, sodium, and potassium) to replenish what's lost through sweat.
Water. Surprised? Plain water is the best way to hydrate, no second guessing necessary. And this stylish water bottle makes it easy to drink enough.
Hot and warm water is just as hydrating as cold and ambient water. However, we consume both in very different ways and often for quite clearly different reasons. When we heat up our water for tea or coffee, we do so with the aim of consuming a delicious drink to wake us up, or perhaps help us drift off to sleep.
Heart-healthy drinks (other than water)
Five key signs of dehydration include thirst, dark/less urine, dry mouth, headache, and dizziness/lightheadedness, signaling your body needs fluids, with reduced urination and darker urine being key indicators you aren't getting enough water. Other signs include tiredness, fatigue, cool extremities, and in infants, fewer tears when crying or sunken eyes.
Sources of Electrolytes
Some beverages naturally contain electrolytes. Examples include: Milk (high in calcium, sodium, potassium, and phosphorus) Orange juice and coconut water (high in potassium)
Healthcare providers don't recommend beverages containing alcohol or caffeine for optimal hydration. These fluids tend to pull water from your body and promote dehydration. Fruit juice and fruit drinks may have too many carbohydrates and too little sodium, and they may upset your stomach.