Guide to Casein Protein Powder for Bodybuilding

Casein protein is an important supplement for bodybuilders, as it helps to build and maintain muscle mass. But that’s any other protein powder, right? What’s so unique about casein?

This guide will discuss what casein protein is, its benefits, and how you can use it effectively in your bodybuilding routine.

What is Casein Protein Powder?

Casein protein is a slow-digesting dairy-based complete protein coming from cow’s milk.

Casein is very present in the milk, up to 80%, and is the exact reason why milk is white. It is also the protein we consume through dairy products throughout life.

Compared to many other types of protein supplements, especially whey, casein takes longer to digest, meaning it provides your muscles with a prolonged supply of nutrition over the course of the day.

Finally, some studies have suggested that casein may help regulate weight by increasing feelings of fullness after eating, but more on that in a second. [1]

Benefits of Casein Protein

Casein protein is a complete protein containing all of the essential amino acids your body needs for muscle growth, repair, and maintenance.

When you train, your muscles are under tremendous stress, thus the need for a steady supply of nutrition. And what’s perfect for starving muscles? A whole lot of amino acids, which casein can provide.

One thing that sets casein apart from its dairy counterpart, whey, is its slow release of amino acids.

Being slow-release, casein can help your muscles recover and grow for hours after ingestion. With a steady stream of amino acids, your body can repair and build muscle even as you sleep, making your recovery more efficient. [2]

Finally, many praise casein as their number one helper on their weight-loss journey as it increases feelings of fullness, reducing your cravings for junk food – or food in general.

This can be incredibly helpful when you’re in a calorie deficit trying to shed some fat, prepare for a show, or just overall lose some weight because you need to.

To be fair, this is not some kind of magic protein that helps you lose fat but keeps your muscle on, but research has proven its benefits when it comes to weight loss.

In addition to all those body-transforming benefits, casein is also very rich in calcium, has a positive impact on triglyceride levels, helps strengthen the immune system, could help regulate blood pressure, and so on.

Casein vs. Whey Protein

It’s hard to compare the two, especially because they’re arguably the best options for bodybuilders.

Sure, there are differences between the two, with the main one being the rate at which they are digested. Whey protein is fast-digesting and is typically used pre, during, or post-workout, while casein is slow-digesting and is primarily used as a meal supplement throughout the day and before sleep.

Does this make one better than the other? Not necessarily. It all depends on your training and dietary needs.

One could even argue the best way to use them is to combine them, so you experience the benefits of both.

If you want to get a full comparison of casein and whey protein we wrote a full article about it here.

Is Casein a Good Alternative to Whey?

Yes, casein is absolutely a good alternative to whey. The best one, probably.

That said, what would be a good alternative?

If you’re vegan and trying to build some muscle, a good alternative to whey certainly wouldn’t be another dairy-based protein. It would be something plant-based instead, such as a pea or soy protein.

But at the same time, if you wish to switch things up a bit and you want to exploit those differences like an absorption rate for a minor gain – this is the alternative to go for.

In a natural bodybuilding competition, every little thing matters. So, feeding your muscles through the night might just make enough difference to help you win your first medal.

How Much Casein Protein Should You Take Per Day?

The Recommended Dietary Allowance (RDA) for protein is 0.8g per kilogram body weight or 0.36g per pound. For example, a 150-pound person would need about 55 grams of protein daily.

But if you’re trying to compete as a bodybuilder – this won’t cut it.

To maximize muscle growth, you’ll need about 0.8 grams of protein per pound of body weight. This means the same 150-pound person would need about 120 grams of protein daily to build muscle effectively.

Out of that 120 grams of protein per day, you should make sure not to consume too much of it in protein powder. A good maximum is one-third of your daily protein intake in protein powder

In this case, it would be 40 grams of maximum casein protein intake per day for a 150-pound person. Make sure to get enough protein intake from real whole foods to maintain good overall health and nutrition. 

Even then, less is usually better. Usually, aim for one serving of casein protein per day, which will be between 20-40 grams depending on the brand. 

Of course, this is only an estimate. Depending on your goals and individual needs, you might need more or less protein than this, alongside many other things and an overall balanced diet.

When Should You Take Casein Protein?

While casein is most often taken right before sleep (usually about half an hour before you go to bed), that is definitely not the only or the “right” time to take it.

Casein can be taken whenever because your muscles need a steady stream of nutrients. More recent research heavily suggests that the timing of your protein intake is not nearly as important as previously thought.

The thing that matters? The overall amount of protein you get per day.

So, if taking casein before bed works for you – great! If it doesn’t – that’s fine too. Just make sure you hit your required protein intake at the end of the day.

Casein Protein Side Effects

There aren’t many serious side effects associated with casein protein.

However, as with any other type of dairy product, it can cause digestive issues in people who are lactose intolerant.

It can also put a strain on the digestive system and cause respiratory issues or induce reactions similar to those of gluten intolerance, but almost all of these are the result of over-indulgence and can be remedied with moderation.

Best Casein Protein Powders

If you’re sold on casein and want to incorporate it into your diet, several top-notch casein powders are available online.

Some of the best options are:

Transparent Labs 100% Grass-Fed Casein Protein
Transparent Labs Casein Protein Powder

With 25 grams of protein and just 0.5 grams of fat per serving, Transparent Labs’ casein powder is a great way to fuel your muscles with slow-digesting protein all night long.

Plus, it contains no artificial sweeteners, thickeners, or colors – so you know exactly what’s going into your body.

MyProtein Slow-Release Casein
MyProtein Casein Protein Powder

Here we have another great option coming in at 25 grams a scoop, with the only noticeable difference being the number of calories.

MyProtein’s casein powder is just 105 calories per serving, making it arguably one of the best options for weight loss.

Optimum Nutrition Gold Standard 100% Micellar Casein Protein
Optimum Nutrition Casein Protein Powder

Finally, we have a classic with Optimum Nutrition’s 100% Micellar Casein protein.

It contains 24 grams of protein per scoop, so it’s the least protein-rich option out of the three, but that certainly doesn’t make it any less suitable for anyone looking to pack on or shed some pounds.


In conclusion, casein protein is a great way to ensure your muscles get enough nutrients if you’re going hard at the gym or doing any athletic activity.

Whether you’re trying to bulk up or make weight for a competition while retaining most of your lean muscle mass, adding casein protein to your daily routine can make a difference in your results, so don’t hesitate to try it out.

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