Protein Shakes: Should I Mix Protein Powder With Milk or Water?

  • By Rebecca Kesner
  • 8 minute read
3 shakes lined up made with either protein powder with milk or water

On the label of any protein powder supplement, the advice states that it can be mixed with water or milk. But does it make that much of a difference? Surely it's simply down to personal preference?

Well, there is actually a lot more to this debate than we may think!

This article delves into the differences between the two and which option you should choose based on your goals.

Let's go.

What are the Benefits of a Protein Shake?

Man in gym post workout with towel around shoulders drinking a protein shake.

Protein shakes, particularly those made with whey protein, are more than just a convenience for those with a busy lifestyle or athletes with rigorous training schedules. They serve a multitude of purposes, from supporting muscle repair and growth to ensuring adequate protein intake for those on specific diets. Below are the expanded benefits, categorized for easier understanding.

Enhanced Muscle Growth and Repair

Accelerated Muscle Recovery

Whey protein, rich in essential amino acids, plays a crucial role in muscle recovery post- exercise. Using whey protein isolate, especially when mixed with water, aids in repairing muscle tears caused by intense physical activity, speeding up recovery times and reducing muscle soreness.

Promotion of Muscle Hypertrophy

Back shot of bodybuilder doing pull ups.

Regular consumption of protein shakes, especially when combined with resistance training, can help build lean muscle mass through muscle hypertrophy — an increase in muscle size. This is due to the availability of amino acids, which are the building blocks of muscle tissue.

Supports a Range of Bodily Functions

Immune System Boost

Whey protein contains immunoglobulins and lactoferrin, which help strengthen the immune system by fighting off bacteria and viruses.

Enhances Metabolic Health

Protein has a higher thermic effect compared to fats and carbohydrates, meaning it burns more calories during digestion, thus supporting metabolism and helping you lose weight by managing caloric intake more effectively. gain muscle mass consuming whey protein calorie deficit diet mixing protein.

Ideal for Various Diets and Lifestyles

Supports Plant-Based Diets

Examples of plant based proteins.

For those following plant-based diets, getting sufficient protein can be challenging. Whey protein (or plant-based alternatives) shakes provide a convenient way to supplement dietary protein, ensuring nutritional needs are met.

Convenience for Athletes and Active Individuals

Female runner with dark hair and headphones stopping in cityscape to drink protein shake.

Athletes and individuals with higher physical activity levels may have increased protein requirements. Protein shakes offer an easy and effective way to consume the necessary protein without the need for constant meal preparation.

Accessibility and Nutritional Value

Easy to Obtain

Whey protein supplements are widely available and relatively inexpensive, making them accessible to a broad audience. This ease of access encourages consistent protein intake for individuals aiming to meet their nutritional goals.

Complete Amino Acid Profile

Whey protein is a complete protein, meaning it contains all nine essential amino acids necessary for human health. This makes it an excellent choice for supporting overall bodily functions and muscle repair.


Economical Source of High-Quality Protein

Compared to other protein sources, whey protein offers a cost-effective way to consume high-quality protein, especially considering its complete amino acid profile and high biological value.

So, which liquid should you be mixing it with: water or milk?

Whey Protein With Milk: Pros and Cons

Protein shake being made with milk.

If you’re on the journey to making more muscle gains, milk would definitely be the better choice to mix with protein powder. Why? Simply because it has extra nutrients and calories, thus boosting its protein content and density.

For example, adding 200ml of semi-skimmed milk will add 7.2g of protein, 100 calories, 8.6g carbohydrates, and 3.6g of fat. While your shake will already have a decent nutritional profile, milk will only add more of the good stuff.

The additional protein and amino acids contained in the milk will help to stimulate protein synthesis more effectively than water, too.

Luckily, there are different kinds of milk we can use to better suit our goals. The example above is based on semi-skimmed milk, but if you really wanted to boost the calories, whole milk would be a better choice. Alternatively, skimmed milk will provide fewer calories, ideal for someone on a calorie-controlled diet.

In terms of nutrients, drinking your protein shake with milk will also provide you with more calcium. 200ml of milk contains around 250mg of calcium, so your protein shake mixed with milk will provide you with around 28% of your daily calcium allowance.

Calcium is an essential mineral that plays a key role in strong bones, blood clotting, energy-yielding metabolism, and muscle function.

Another benefit of drinking your protein shake with milk is hydration.

While you wouldn’t really be drinking a protein shake with the purpose of hydrating, it is still important to maintain good hydration levels throughout the day as this would help support normal muscle function and avoid decreased performance associated with dehydration.

So, it may be a surprise to find out that milk is actually more hydrating than water! Many studies have found that milk has a higher hydration index than water, helping to replace sodium that is lost through sweat while helping the body retain fluid more efficiently.

Obviously, this doesn’t mean that we should now start drinking more milk than water, but for when you really need to boost your fluid intake and get hydrated after a sweaty session, milk may be a good option at these times.

Going beyond nutrition value and hydration benefits, drinking your protein shake with milk may also have a nicer taste and texture due to the added sweetness and thickness.

Enough of the upsides - there must be some pitfalls of drinking your protein shake with milk, right?

Well, milk can take a little longer to be absorbed when compared with water, which could mean that it takes longer for the protein to absorb.

While this isn’t necessarily a bad thing as it would mean that your body is getting a slow release of protein and amino acids, it’s not the best option if you’re wanting a quick replenishment of protein.

Whey Protein With Water: Pros and Cons

Scoop mixing protein powder with water.

Mixing protein powder with water would be the easiest, cheapest, and more convenient option over milk. Though, as we have established, water has no nutritional value, so will not add any more protein or calories to your shake. Which has its own benefits for those concerned with calorie intake.

However, it really does depend on personal preference.

As we have mentioned, milk would slow down the absorption of the protein, whereas water wouldn’t affect it. This would make for a quick-release protein shake, ideal for fast replenishment after a training session. Using whey protein isolate with water also ensures faster digestion and absorption, making it suitable for those who are lactose intolerant.

Additionally, drinking water with your protein shake would mean you are drinking more water throughout the day. Water is essential for a wide range of bodily functions, so your protein shake would be providing a range of benefits despite not being nutritionally enhanced.

So, while a shake mixed with water may not be as creamy or dense as it is with milk, it would definitely be the more quicker and convenient option than bringing a carton of milk to the gym!

What About Plant-Based Milk?

Different types of non dairy milk types in bottles. Vegan protein powder shake.

We can't talk about milk without mentioning the plant-based options.

For those with dietary preferences, lactose intolerance, or anyone looking to experiment with different tastes and nutritional profiles. Plant-based milks like soy milk, almond milk, and oat milk have become popular choices, each bringing its unique set of benefits to your post-workout shake.

Soy Milk

A standout for its extra protein content, soy milk is a robust option for those seeking a vegan protein boost. With a nutritional profile that closely mirrors that of cow's milk, soy milk not only contributes to aiding muscle recovery but also provides a considerable amount of protein, making it an excellent choice for those who are lactose intolerant or following a plant-based diet. Its naturally creamy texture mimics the consistency you'd expect from traditional dairy.

Almond Milk

Known for its light texture and slightly nutty flavor, almond milk is a low-calorie option that still allows for a satisfyingly creamy shake. While not as high in protein as soy milk, it's enriched with vitamins and minerals, making it a healthy addition to your diet. Almond milk is particularly appealing for those monitoring calorie intake without sacrificing taste.

Oat Milk

Oat milk stands out for its exceptional creaminess and sweet, mild flavor, making it a favorite among coffee enthusiasts and shake lovers alike. It's an excellent source of carbohydrates and fiber, providing sustained energy and can help with digestion.

Nutritional Benefits

Plant-based milks can offer more than just a lactose-free alternative. Many are fortified with calcium and vitamin D, similar to fortified cow's milk, and provide a range of nutrients beneficial for overall health. Opting for a plant-based milk in your shake can cater to your dietary preferences while still supporting your fitness and nutritional goals.

Incorporating Vegan Protein Powders

For an extra protein punch, consider adding vegan protein powders to your plant-based milk shake. Pea, hemp, and brown rice protein complement the nutritional profile of plant-based milks perfectly.

The Ultimate Protein Shake Recipe

Now we’ve explored the benefits of mixing your protein shake with milk or water, let's put that knowledge into practice with a delicious and nutritious recipe designed to help you achieve your fitness goals.


  • 1 scoop of whey or vegan protein powder

  • 200 ml of your choice of milk (skimmed, soy, almond, etc.)

  • 1 tablespoon MCT oil (optional for added energy)

  • ½ banana for natural sweetness

  • A handful of spinach for extra fiber and minerals

  • Ice cubes


  • Combine all ingredients in a blender.

  • Blend until smooth.

  • Enjoy immediately for best taste and nutrient absorption.

If your training goals include achieving faster muscle recovery, accessing more energy, or losing weight, you might want to consider adding a tablespoon of MCT oil into your protein smoothie.

Benefits of Adding MCT Oil to Your Protein Shake

Adding MCT oil to your whey protein shake to help with weight loss.

MCT oil, or Medium Chain Triglyceride oil, is a unique form of saturated fatty acid that has been praised for its ability to provide quick energy to the body and support fat burning.

Unlike other fats, MCTs are metabolized differently by the body: they are rapidly absorbed and immediately transported to the liver, where they are converted into ketones.

It has been shown to increase the release of two hormones that promote the feeling of fullness in the body: peptide YY and leptin.

Adding a tablespoon of MCT oil to your protein smoothie could help curb your appetite and prevent overeating throughout the day, which is crucial for those trying to lose weight.

In addition to that, MCTs contribute to a higher thermogenic effect and improved fat oxidation, which can accelerate fat loss when combined with regular physical activity and a balanced diet.



Whey protein powder is one of the most popular sports supplements in the fitness industry. Though, as we're always looking to optimize our nutrition strategies, we have delved into the debate on which liquid is better in a protein shake: milk or water?

Well, the final answer is really down to personal preference.

Milk can provide additional protein, fats, carbohydrates, and calories, which is a huge benefit for someone who is looking to increase energy intake.

It's also the best option if you want a slower release of protein and nutrients to aid recovery, as well as better hydration.

Though, this may be a less convenient option than water. You may want a quick protein replenishment, or not want to take a carton of milk to the gym. In this case, water would be the better option.

Plant-based milk also comes into this debate, being a creamy, tasty texture for minimal calories. This option should also be considered if it fits your goals!

All in all, investing in a good quality protein powder would ensure you get the nutrients you need alongside good taste and texture, so whichever liquid you choose to mix in would simply be a small bonus!