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March 26, 2021 7 min read

If you are like us and live a healthy lifestyle, or are trying to start or maintain a healthy lifestyle, you have most likely heard of whey. If you are trying really hard to build muscle and lose fat, then the chances are higher that you have actually used whey before. But do you know? Or which form of whey protein is for you? It’s okay, you are not alone. It is not uncommon for personal trainers to recommend their clients start adding whey protein to their diet, but that doesn’t mean their clients understand why it’s what they’re recommending for successful weight loss.

To help you understand which form of whey protein will be the most beneficial to you, your diet, and your weight loss goals, we are taking the two most popular forms of it and putting them head-to-head. To see which one comes out on top, keep reading. First, we are going to answer the most important question of them all.

man wth whey protien

What is Whey Protein Anyways?

Great question. In short, it is the fast-digesting fragment of dairy protein. The process of forming cheese or yogurt from milk leaves behind a liquid called whey.

There are two primary proteins in milk: whey protein and casein.

They are both considered high-quality proteins meaning they contain all nine of the essential amino acids, which our body cannot produce all on its own. To refresh your memory, the  essential amino acids include:

  1. Histidine
  2. Leucine
  3. Isoleucine
  4. Threonine
  5. Lysine
  6. Methionine
  7. Phenylalanine
  8. Valine
  9. Tryptophan

PRO TIP - If you are looking to build muscle, Branched-Chain Amino Acids (BCAAs) will aid in the process. This includes isoleucine, leucine, and valine because they are vital to muscle protein. 

Whey protein is one of the easiest accessible complete proteins available! Actually, whey is one of the most natural protein sources on earth. On top of that, it is available in multiple forms; the two most common being whey protein isolate (WPI) and whey protein concentrate (WPC). Both forms stem from raw milk and go through basically the same process; however, whey protein isolate goes through a more strenuous process leaving it with fewer calories, carbs, and fats than whey concentrate. But does that mean it’s better? Let’s find out!

Whey Protein Isolate Explained

As explained, the isolate is made using the same initial process as the concentrate but it is passed through more filtration than the concentrate to remove lactose and fat from the isolate. The cold filtration the isolate goes through causes the protein to be purer. In fact, after filtration, it will have a 10-15% higher protein density than the concentrate meaning the isolate is 90-95% protein! However, the additional filtration means it takes longer to make which in turn means whey isolate is typically more expensive to purchase. In general, users of WPI state it has a smooth texture which they appreciate.

Whey Protein Concentrate Explained

As you know, it takes less processing to create the concentrate. It still goes through the liquidation process, but instead of being sent through the cold micro-filters, the liquid is dried until it turns into powder. Once the process is complete, the concentrate will contain 80% protein and 20% fat, carbohydrates, and lactose. Remember, cold filtration is what removes the fat from the liquid. Due to the fact that the concentrate contains sugars (carbs and lactose), it tends to have a sweeter taste but can have a gritty texture which users complain coats the mouth.

Essentially, since whey isolate contains less fat and calories than whey concentrate, it is safe to assume that increasing the portion of concentrate used daily would be equivalent to taking a normal dose of whey isolate. For example, if you are trying to have a shake with 20 grams of protein, you will need to add more of the WPC (concentrate) than you would of the WPI (isolate). Below is a chart to help you see the differences visually. This is based on 100- calorie serving of each.

Whey Isolate

Whey Concentrate





23 grams

18 grams


1 gram

3.5 grams


0 grams

1.5 grams


up to 1 gram

up to 3.5 grams




There is actually a third form of whey protein that is gaining popularity. It is called hydrolyzed whey protein isolate. By exposing WPI to enzymes, the bonds holding the amino acids together begin to break making it the easiest protein for digestion, meaning it is quickly absorbed into the gut and easy on the stomach. 

The Main Difference

In summary, the main difference between the two forms of why protein is the cold micro-filtration step, which is what removes the fats, carbohydrates, and lactose from the liquid resulting in a higher amount of pure protein. 

man in gym drinking powder

Benefits of Taking Whey Protein

Regardless of its form, whey protein has many benefits, including:

  • Accelerates weight loss
  • Lowers blood pressure
  • Decreases inflammation
  • Stimulates muscle growth
  • Reduced recovery times

You will reap the benefits of the protein intake whether you choose a concentrate or an isolate.

The most important factor about having protein in your diet is that you are meeting the ideal daily intake for your body. The only time you really need to stick to one or the other is if you are on a diet that requires strict limits on your intake of carbs, fat, and calories. If this is the case, you will want to stick to whey protein isolate due to its purer protein content. 

However, if you are looking to save money, you will find that whey concentrate is typically more affordable. Remember, choosing to take a slightly higher dose of the concentrate is equal to the same amount of protein from a normal dose of whey isolate. In addition, it is not uncommon for protein powder and supplements to contain amounts of both whey isolate and whey concentrate. Therefore, if you are looking for a specific form of whey, be sure to read the nutritional and ingredients label on the product before making your purchase. 

What Is Casein?

You may have heard of casein if you have done a lot of research on whey protein, but what is it? Casein is the other protein found in milk and other dairy products.

It works similarly to whey protein and also contains all 9 essential amino acids.

During the liquifying process, the milk begins to curdle and separate from the remaining liquid. As you already know, the liquid left behind is whey protein. The curdles that result from the process are made up of casein. Before the process of turning milk into cheese, approximately 20% of the protein within the milk is whey while the remaining 80% is casein.

Why Whey Over Casein?

The body absorbs casein differently than whey. Due to casein’s natural “stickiness,” it takes the body longer to digest and commonly results in bloating. For this reason, supplements containing casein are typically promoted as appetite suppressants because they tend to leave you feeling fuller for longer. However, once proteins reach the intestines, the body digests whey and casein exactly the same way.  In addition, whey is great at promoting the production of new protein in the muscles, whereas casein is not. 

PRO TIP: When shopping for whey protein products you will likely come across some branded with “protein-blend” on them. This means the product contains a mixture of whey isolate (WPI), whey concentrate (WPC), and milk powders.

Are There Any Side Effects of Whey Protein?

Being something that our body needs and benefits from greatly, whey protein is typically acknowledged as safe; however, as with most things, there is a chance of some slight side effects.

The most common side effects experienced include:

  • Indigestion 
  • Gas and diarrhea
  • Constipation (typically lactose-related)
  • Headache
  • Bloating
  • Extreme thirst
  • Nausea
  • Appetite suppression

Whey protein users most often experience side effects related to how their body digests it and their tolerance for simple sugars, i.e. carbohydrates. Therefore, it is important to keep this in mind when taking whey protein, of any form. 

Which is better?

Ultimately, the best choice for you will depend on your health, nutrition, and fitness goals. As mentioned, you will see the benefits of either fairly quickly when combined with a healthy diet and regular exercise. If you recall, the main difference between WPI and WPC is the number of carbs (sugars) and fats remaining in the protein.

Below are different reasons to consider one over the other to help you decide which is best for you:

  1. If your goal is to build lean muscle mass or to gain weight, you will want to consider whey protein concentrate. 
  2. If your diet requires strict daily calorie-intake to help reduce weight, consider a whey protein isolate product.
  3. If you like to save money, it is likely you will find the concentrate to be more affordable.
  4. If you are using protein supplements as meal replacements, stick to concentrate since it retains some of the sugar and fat. Additionally, look for protein products with casein in the ingredients. 
  5. If you have a high sensitivity to lactose, which can lead to stomach issues, we suggest purchasing whey isolate. When using a concentrate, it is common for those with lactose intolerance to “reject” the thicker texture and lactose resulting in inflammation and irritation of the gut. 

When looking to purchase whey protein, it shouldn’t be too hard to find. It is available at most supermarkets and health food stores. They can also be purchased online.

Whey is most commonly found in powder form which is later added to a protein shake, smoothie, or juice, but it is also found in protein bars so be sure to be on the lookout for those as well for additional protein benefits. 


Wrapping it Up

In the beginning, we learned that whey protein is one of two high-quality proteins found in dairy products. The second high-quality protein being casein, which is the curds left behind during the liquidation process of making milk into cheese or yogurt. Even though similar to whey, casein takes longer for the body to digest making it better for appetite suppression as opposed to weight loss. 

We also learned that whey protein is available in many forms; however, the two most popular forms of it are whey protein concentrate (WPC) and whey protein isolate (WPI). The main difference being the isolate is created from further filtering than whey concentrate.

The additional filtration leaves the isolate without fats, carbs, and sugars (lactose) making it 90-95% protein.

Depending on your fitness objectives and nutrition goals is how you will decide whether whey isolate or concentrate is best for you. As we mentioned, regardless of what you choose, you will notice the benefits of your increased daily protein intake.

With that in mind, if your fitness objectives include building lean muscle mass, you will want to be on the lookout for whey concentrate. On the contrary, if you are counting calories to lose weight, you will find that you get better results when using whey isolate.

Pro Tip: We have a large selection of delicious whey protein powders for you to choose from which you can find here.