Protein Powder Shakes: With Cow’s Milk, Water or Other?

milk or water for protein powder

One of the biggest debates in the fitness world is whether to mix your protein shake with milk or water. We’ll admit, it’s a question we’ve often asked ourselves, too - just what is the best liquid to mix with protein powder? And the truth is, there isn’t one straightforward answer to that question.


OriGym’s comprehensive guide will explain what to mix protein powder with to meet your tastes, as well as answering any questions you may have. Whether it’s about having protein powder with water or milk, or mixing plant-based protein powders to maximise your gains and your protein intake, we’ve got you covered!

We’ve compiled all the information in one easy-to-digest overview, so you can continue to train as effectively as possible. Read on to find out whether you should have protein shakes with milk or water!


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What is Protein Powder?

This may seem simplistic, especially as you’ve just clicked on this article, but it’s important to define what we mean by protein powder.

As you may already know, protein powder is one of the most used dietary supplements there is (among the general public and athletes alike). These products are typically rich in essential amino acids, particularly branched chain amino acids (BCAAs) which research has shown can trigger muscle protein synthesis

Muscle protein synthesis is where the body produces proteins to repair muscles after strenuous or intense exercise. Without this process, our bodies wouldn’t recover properly, and we wouldn’t be able to build muscle in the same way that we do. And recovery is hugely important in fitness - our guide to the importance of rest days and how many you need is a must read if you’ve ever wondered how to recuperate as effectively as possible.

Anyone who is involved in challenging exercise is advised to consume a high-quality protein source, such as a protein shake with milk or water, following exercise in order to initiate muscle protein synthesis as soon as possible (as exercise typically involves damaging muscle tissue).

However, these protein powders can be utilized throughout the day, and are not simply a tool to optimise recovery post-exercise/activity. They can also be consumed with many different mixing ingredients, such as a protein shake with water or milk (either cow’s or plant-based).

In this article, we'll cover the most popular options for what to mix protein powder with (usually a protein shake with milk or water, but there's also a few options you may not have considered! ), as well as discussing other alternatives and how timing can factor into mixing ingredients.

What is a Protein Powder Shake?

Essentially, a protein shake is a protein powder (such as the ones we’ve just discussed) mixed with a liquid (we’ll get onto what is the best liquid to mix with protein powder in our next section).

There are many different varieties of protein powder mixes available commercially. Whey protein powder (sourced from cow’s milk) was the first example of a commercially available powder mix aimed at exercisers. It is widely used, and accepted, as an invaluable dietary tool to increase muscle mass, improve body composition and continue to develop. OriGym’s comprehensive look at the benefits of whey protein delves deeper into the superb supplement.

Casein protein (the other major protein found in cow’s milk) soon followed, and was marketed as a slower digesting alternative to whey which, studies have found, may be beneficial to use prior to sleep to enhance recovery.

Over the last several decades, other protein sources have been isolated and manufactured into powder forms. Examples of these include

  • Beef
  • Egg
  • Soy
  • Pea
  • Rice

There’s also been significant developments in protein powders that cater to specific dietary needs, such as vegan or gluten-free protein powders (hemp and spirulina, for instance).

Companies may also combine various sources into a “protein blend”, most commonly seen with whey and casein, but also with many vegan products too. Manufacturers of vegan friendly products will typically combine one or more plant protein sources due to their lack of a complete or sufficient amino acid profile. 

Combining one with another complimentary source mitigates this issue and allows for similar effectiveness when compared to an animal-based protein powder product.

But what next, after you’ve got your ideal protein powder? Read on to learn more about what to mix protein powder with!

What Can You Mix Protein Powder With?

If you’re wondering whether to mix your protein shake with milk or water, there unfortunately isn’t one single answer.

Protein powders, while incredibly useful as we’ve just discussed, cannot be consumed on their own - they need to be mixed with a liquid so that they form a mixture or “shake”. Our selection of the best protein shakers will give you the edge when it comes to mixing!

Regardless of the type of protein powder being consumed, there are generally 3 options for what to mix protein powder with in your protein shake:

  • Cow’s Milk
  • Water
  • Plant-Based Alternatives (such as protein powder and soy milk, or almond milk and protein powder)

Each of these options for what to mix protein powder with has their own advantages and disadvantages, and we’ll now analyse each option.

What Are The Benefits Of Having Protein Shakes With Milk?

Many people’s immediate thought when it comes to protein shakes is “can you mix protein powder with milk instead of water?”. And the answer is a resounding yes!

Let’s explore the first option in making a protein shake with milk or water, and why you might choose milk over water in your shake!

#1 - Protein Rich

Cow’s milk is naturally rich in protein containing both whey and casein proteins (in a ratio of 20:80 percent), meaning milk with protein powder gives you a double helping of protein! Manufacturers isolate these proteins from milk to produce the now globally popular commercially available powder mixes. Of course, there are plenty of options for other protein powders (such as the ones we looked at earlier), but whey and casein powders have a higher protein content than others. OriGym’s pick of the best casein protein powders explores just a few of these options.

The above table demonstrates the nutrient contents of cow’s milk and its variations.

As we can see, each specific type of milk provides a significant amount of protein, in addition to the protein powder. All of these figures and measurements are what we’d recommend for a good shake, so you know exactly how much milk to mix with protein powder.

For athletes looking to increase lean muscle mass, body mass and or requiring greater energy intake to meet energy output demands, mixing protein powder with milk could be the best option to mix with.

#2 - Additional Vitamins & Minerals

how much milk to mix with protein powder

Cow’s milk is also rich in other dietary components too. These all provide additional benefits to other parts of our bodies that we may not necessarily consider when planning our diets. Cow’s milk offer a great intake of protein, plus:

  • Calcium - this is traditionally associated with strong bones and healthy teeth, but calcium also helps the heart, muscles and nerves to function properly.
  • Vitamin B12 - this specific vitamin helps maintain and repair our nervous system, as well as preventing certain types of anaemia.
  • Iodine - this is necessary for maintaining a healthy metabolism, as well as making thyroid hormones (which help with growth and cell repair). Studies have even shown that this is an area where many people have an unnoticed deficiency!
  • Magnesium - this is an essential mineral for a wide array of processes in your body, such as regulating blood sugar levels and maintaining healthy blood pressure.

As if that wasn’t enough, we’ve just seen in our table above that cow’s milk with protein powder provides additional protein, vitamins, minerals, carbohydrates, fats and energy. It really is the complete package!

#3 - Post Workout Hydration

Milk may not be your first choice when it comes to hydrating your body, but this is one surprising benefit of having milk in a protein shake!

According to the American Journal of Clinical Nutrition, milk provides better hydration than a number of other beverages, including some sports energy drinks! So, not only is your protein shake with milk providing nutrients and muscle repair, but it's also keeping you well hydrated and replenishing fluids!

Studies have even identified cow’s milk on its own as a potentially useful post-exercise recovery beverage for athletes, with researchers highlighting it as a high-quality protein source capable of driving muscle recovery.

Additionally, combining whey and casein sources, as well as a protein and a carbohydrate source may be superior to recovery and adaptation over a single source protein meal.

So to answer that initial question of “can you mix protein powder with milk?”, not only can you mix the two, we’d recommend doing so!

Now let’s look at the other side of mixing a protein shake with water or milk...

What Are The Benefits Of Having Protein Shakes With Water?

Milk is, of course, not your only option for what to mix protein powder with - water is also a great choice. 

#1 - Faster Absorption

Now, it’s first important to make clear that, at least from a nutritional standpoint, water doesn’t contribute anything aside from it’s hydrating properties. 

However, this could be hugely beneficial - it may also allow for a more rapid absorption of the protein powder it has been mixed with as it can create a less viscous or thick mixture. By making the protein shake more easily swallowable and digestible, it means that your body can have more ready access to all the nutrients that a protein shake provides.

This also comes with the additional benefit that, after a particularly difficult workout, protein powder with water allows for more adequate hydration, and the body can more easily digest the nutrients that the protein powder provides. 

Whilst cow’s milk and protein powder may offer additional nutrients and other dietary components, it also contains casein protein. Casein protein forms a gel-like substance (compared to whey which forms a solution), and this is known to absorb slower than other proteins.  

Additionally, it may also slow the absorption rate of other nutrients, which could in turn slow the recovery process to a degree as it may take nutrients longer to get to the muscle tissues that require them.

#2 - Lower Calorie

protein powder with water

This is one of the key differences between water and milk.

For athletes or keen exercisers who are looking to reduce their calorie intake or simply utilize energy elsewhere in their diet, mixing protein powder with water may be a more desirable approach. 

As we saw in our section on the benefits of having milk with your protein powder, milk also comes with multiple other vitamins and nutrients, including fats and carbohydrates. This could be detrimental if you’re looking to slim down or are watching your calorie intake.

And if you are calorie counting, our list of the best healthy cereal bars means you can still snack and stay slim.

#3 - Accessibility

Finally, on a base level, it’s a much more accessible option - having protein powder and milk isn’t necessarily an option for everyone (whether that’s for dietary needs, ethical beliefs, or even just because you don’t enjoy the taste or viscosity of milk). 

Plus, water and protein powder can be made up at the gym, meaning more convenient access to the benefits of protein powder. Protein shakes are ideal (whether that’s pre, during, or post workout), and having this increased availability means that they can be incorporated into the exercise routines of even the busiest of gym goers.

So, now that we’ve considered whether to have a protein shake with milk or water, let’s go on to some options you may never have thought about!

What Are The Benefits Of Having Protein Shakes With Milk Alternatives?

Our final option for what to mix protein powder with are plant-based milk alternatives. Many people only ask themselves “should I mix my protein shake with water or milk?” and often overlook plant-based options such as almond or oat milk.

Now, you might choose to mix their protein powders with plant-based milk alternatives for ethical or dietary reasons,  but did you know that plant-based protein shakes offer benefits that a protein shake with milk or water may not have?

#1 - Boosted Vitamin Content

One of the surprising benefits of plant-based milk alternatives is that many of them are fortified with various vitamins and minerals and, in some cases, even provide more of these essentials than found in cow’s milk!

A great example of this is almond milk. These have a higher calcium content than cow’s milk, and are available in both sweetened and unsweetened forms, so there is even a choice here! 

It has also been highlighted that plant-based milk substitutes may also confer additional benefits thanks to their phytochemical content (naturally occurring bioactive compounds found in plants).

These vitamins and minerals are essential for living a healthy lifestyle - we’ve gone into much greater depth in our guide to the best vitamins to combat tiredness and fatigue.

#2 - Vast Range of Choices

In the below table we’ve touched on a few of the most common types of milk alternatives, and that is perhaps one of the biggest advantages of using milk alternatives with protein powder - the variety.

should I mix protein powder with milk or water

This array of flavours, textures and compositions ensures that, even if you can’t have one particular type of plant-based milk (hazelnut, for instance) due to allergies or personal preferences, there are a significant number of options still available.

Many of these alternatives will also be lower in calorie per serving than milk and richer in carbohydrate over fat (this is not always the case however and it’s important to read the label to make nutritive comparisons).

The table above highlights the nutrient contents of some of the most popular plant-based milk variations.

#3 - Environmentally Friendly

milk and protein powder

Because they don’t rely on animal production facilities, or even cows themselves, the impact on the environment by plant-based milk production is as minimal as it possibly can be. Even the packaging is generally more recyclable than traditional milk bottles!

Studies have confirmed this reduced global impact, and have shown that milk alternatives are often more environmentally friendly, and ethically sourced. Their sustainability, too, means that they can be mass produced for many years to come without having a drastic impact on the environment.

Ultimately, plant-based milks offer a “middle-ground” between water and cow’s milk; they’re rich in a variety of nutrients, possibly lower in energy contribution, more sustainable and provide a vast range of options for which to choose from.


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Are There Times Where Water Is Better Than Milk?

One other important aspect to consider is when it comes to protein shakes is which is most beneficial - a protein shake with milk or water. As we’ve just discussed, each has their own pros and cons, but there are times where one is more useful or appropriate than the other.

One important thing to note is that, as water forms a more rapidly absorbable solution comparative to milk, it may be better to utilize it in and around exercise. We already discussed water’s more ready availability, and this ensures that it’s an ideal mixer for protein powder when exercising. 

And stay motivated as well as hydrated with OriGym’s report on the definitive workout playlist, and add some rhythm to your routines!

However (when thinking about having a protein shake with water or milk) milk with protein powder is equally beneficial, but in different ways. As previously mentioned, milk has a high casein content (along with whey). Due to its casein content, milk and protein powder may be a more viable mixing option if there are extended periods between meals or before bed.

It should be noted however that, even when incorporating cow’s milk as a mixing ingredient post-exercise, studies have shown that recovery does not appear to be impeded. Instead, data has shown general increases in lean body mass and strength performance when using either mixing ingredient.

Finally, plant-based alternatives to milk (such as protein powder and coconut milk) form a middle ground between water and protein powder, and protein powder with milk. 

Our recommendation for these alternatives would be to use them in a similar capacity to cow’s milk and protein powder, as they have similar nutritional values (aside from protein), and cannot be absorbed as quickly as protein powder and water can.

Can I Use Both Milk and Water for My Protein Shake?

Many people only consider having their protein shake with water or milk, but it’s important to also consider whether you can have two different liquids mixed together in your shake. 

Well, the answer is a definitive yes!

There’s no risks in having a protein shake with both milk and water, and this can have its own  benefits associated with it, too! If you’re looking to cut calories a little, or have a mild intolerance of milk or lactose, then mixing your milk with water can be ideal.

As we’ll explore in more detail a little later, what you mix with protein powder is all down to personal preference, and as these two liquids can have polarising tastes, a mix of the two can provide a great middle ground.

Should I Blend Protein Powders Together?

It may be more advantageous to mix and blend certain protein sources together, especially when considering what to mix protein powder with. 

For instance, a combination of whey and casein may have greater overall outcomes than one or the other individually. Research from the National Library of Medicine has shown that whey has a great effect on muscle protein synthesis after a meal, whilst casein appears to have a greater effect on reducing whole body protein breakdown. 

Essentially, this means that whey activates a greater number of recovery mechanisms, while casein results in a slower release of amino acids. These combined effects have been found to result in an overall greater protein gain.

This can then be further compounded by using our advice on whether to mix your protein shake with milk or water, and where each is appropriate. 

For instance, for a mid-workout shake, you’d mix your newly blended protein shake with water, not milk. Or, if you’ve finished your workouts for the day, and are looking to enjoy a protein shake to manifest your hard work as muscle gain, we’d recommend having your protein shake with milk, not water

However, vegans should pay particular attention to their protein powder mix. Plant-based protein sources are described as incomplete proteins, meaning they lack one or more essential amino acids. They are also, on average, lower in the amino acid leucine, which is critically important in the stimulation of muscle protein synthesis. 

Studies have discovered that plant-based protein sources have an overall lower anabolic potential than animal-based protein sources (in isolation). Combining two or more complimentary sources can, however, alleviate this issue and provide a complete protein source. 

The possible exception to this is soy protein powder, as it has a higher protein content than other milk alternatives. We’ve explored some of the best soy protein powders, and how they could be ideal if you’re looking to bulk up.

What Should I Mix My Protein Powder With For My Goals?

As we’ve just discovered, water, cow’s milk or a plant-based alternative would all be perfectly viable mixing ingredients to your protein powder of choice. 

Whether you’re blending protein powder with water, or deciding between a protein shake with milk or water, it’s important to be aware of the advantages and disadvantages of each choice. Really, it all comes down to energy intake, and increasing protein / vitamins and minerals consumption alongside your protein powder.

Weight and Muscle Gain

If your goal is to gain weight, build muscle, or your workout routine means you have greater energy demands, opting for cow’s milk with protein powder may be the best option (our recommendation for how much milk to mix with protein powder for maximising gains is around 200ml). It’s also ideal if you don’t have as much time to prepare food, or you have longer periods between meals.

Slimming and Calorie Deficit 

For those looking for something “lighter”, or those who are minimizing or sparing calorie intake, it might be best to opt for a protein shake with water, as this simply offers a way to ingest the protein powder without any additional nutritional or calorific benefits.

Somewhere In Between

Plant-based alternatives fall somewhere between, and would be suitable for those following a plant-based diet. Those who have these dietary requirements should also aim to combine plant protein sources when possible to achieve a complete protein source.

Personal preference will also dictate your choice of mixing ingredient, and whether you opt for a protein shake with milk or water, it’s important to keep your goals in mind - our guide to the best fitness journals will undoubtedly have something to help you keep track as you smash past your milestones. 

Similarly, if your first question is “does protein powder taste better with milk or water?”, this all falls down to personal preference. Milk makes a creamier, thicker mix, whereas water is thinner and perhaps easier to sip during a workout. 

With so many choices for what to mix with protein powder, many of these options are all up to you. Regardless of whether you have your protein shake with milk or water, it’s all about achieving your fitness goals, and continuing to progress!

Before You Go!

Protein powder is arguably the most important supplement to our workouts, and it’s vitally important that you understand what’s best for you and your workout goals - whether that’s a protein shake with milk or water, or a plant-based alternative with your protein powder. 

We hope you’ve enjoyed our guide outlining whether to mix up your protein shake with milk or water, and that you now have a clearer picture of what exactly you might need to progress. 

But, if you’re already clued up on whether to have your protein shake with milk or water, then perhaps a career in fitness is the next step for you on your fitness journey. Our REPS and CIMSPA certified personal training courses are an ideal way to continue progressing in your exercise, and imparting that knowledge to others.

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  2. Caio E.G. Reis, Laís M.R. Loureiro, Hamilton Roschel, Teresa H.M. da Costa, Effects of pre-sleep protein consumption on muscle-related outcomes — A systematic review, Journal of Science and Medicine in Sport, Volume 24, Issue 2, 2021, Pages 177-182, ISSN 1440-2440,
  3. Elif Feyza Aydar, Sena Tutuncu, Beraat Ozcelik, Plant-based milk substitutes: Bioactive compounds, conventional and novel processes, bioavailability studies, and health effects, Journal of Functional Foods, Volume 70, 2020, 103975. ISSN 1756-4646,
  4. Hoffman JR, Falvo MJ. Protein - Which is Best?. J Sports Sci Med. 2004;3(3):118-130. Published 2004 Sep 1.
  5. Hwalla N, Al Dhaheri AS, Radwan H, et al. The Prevalence of Micronutrient Deficiencies and  Inadequacies in the Middle East and Approaches to  Interventions. Nutrients. 2017;9(3):229. Published 2017 Mar 3. doi:10.3390/nu9030229
  6. James LJ, Stevenson EJ, Rumbold PLS, Hulston CJ. Cow's milk as a post-exercise recovery drink: implications for performance and health. Eur J Sport Sci. 2019 Feb;19(1):40-48. doi: 10.1080/17461391.2018.1534989. Epub 2018 Oct 31. PMID: 30379113.

Written by Chris Allsobrook


Chris is a former English teacher, turned content editor. He holds a first-class honours degree in English Language and Creative Writing from the University of Central Lancashire, before going on to complete his teacher training, and obtain a PGCE at Liverpool John Moore’s.

Chris is a keen runner and is currently undertaking both his fitness instructing and personal training qualifications here at OriGym. 

Outside of fitness, you’ll often find him gaming, watching the football, cooking, or spending time with his family.

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