Whey isolate A guide

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There are different types of whey, of which concentrate and isolate are the most common. But in which situations do you specifically choose the slightly more expensive isolate?



For muscle growth you need extra protein, around 1.6 g per kg of body weight per day. In our hectic existence, it is not always easy to get those proteins from regular food, even if that is just as good. Supplementation, usually in the form of powder, offers a solution.

Most protein powders are made from whey. Whey is the liquid that is created during cheese preparation by curdling the milk after adding rennet. The solid components, the curd, remain after the whey has been drained.

Whey protein powders are not only popular among bodybuilders because of their practical benefits (quick to prepare and take with you, relatively cheap). Strictly speaking, whey protein has the most favorable properties for muscle growth:

  • an excellent amino acid profile (making it the protein with the highest biological value) with the highest content of leucine (the main amino acid for muscle growth);
  • the highest digestibility;
  • the highest recording speed.

The latter makes whey ideal to take immediately after training, when the anabolic effect of protein intake is perhaps slightly greater than at other times within the anabolic window of opportunity.


The disadvantage of protein powder is that it does not provide other valuable nutrients, as regular protein sources do. Micronutrients are also important for muscle growth and may even enhance the anabolic effect of protein intake.

It is therefore best to limit the use of whey protein powder to, for example, only immediately after training and/or at breakfast, and to fill in the rest of your daily protein consumption with protein sources from food, such as eggs, meat, poultry, dairy and possibly also some vegetable protein sources, such as legumes.


We know three types of whey: concentrate, isolate and hydrolyzate. The differences are in the protein content (and therefore also the biological value) and the speed at which the protein is digested and absorbed. In addition, there are also ‘blends’. Then you get a mix of several types of whey protein and possibly also other types of protein, such as casein.


Concentrate is the most unprocessed form of whey. This makes it the healthiest of the three types of whey, but processed or unprocessed makes no difference for the absorption of proteins. All large proteins are broken down during digestion into smaller protein chains and individual amino acids. So if that hasn’t happened in the factory yet, it still happens in the intestines.

Concentrate also has a disadvantage: it contains ‘only’ 80% protein. The other 20% consists of water, carbohydrates, milk fat, milk sugar (lactose) and minerals.

Yet whey concentrate is by far the most sold type of whey (usually as the main ingredient of a blend – see below). This is partly due to the good taste and solubility. In addition, concentrate is usually a bit cheaper than other types of whey.


However, if you want whey that is more pure and therefore contains less ‘by-product’, then whey isolate is a good option. Isolate undergoes an extra treatment, which means that it contains less fat, milk sugar and regular sugar. Isolate usually contains about 90% protein, sometimes even more, up to 93 percent.

Overall, isolate has a slightly higher biological value than concentrate, is lower in calories and may be better for people with some lactose intolerance (although isolate is not completely lactose-free).

Due to the processing, the isolate variant does contain (somewhat) fewer so-called bioactive peptides, so that the beneficial health effects of these are less than with concentrate.

However, the main disadvantage of whey isolate seems to be the price: it is usually a bit more expensive than concentrate, but not to an alarming extent.


Enzymes have been added to the third whey variant, hydrolyzate, so that the protein is, as it were, pre-digested and absorbed even faster by the body. More precisely, the amino acid chains (the peptides we were talking about) in whey hydrolyzate are split into shorter chains and ‘free’ amino acids, which reach the blood and therefore the muscle more quickly. Hydrolyzate therefore has the highest absorption rate and the highest biological value of all proteins: 150. In addition, it dissolves slightly better than other whey powder types.

Now the absorption of proteins is again not a matter of the stopwatch and a biological value of 110-125 (like that of concentrate) is more than fine. Remember that any good quality whey variety will provide you with all the essential amino acids in the right proportions. As a result, we do not really see any added value in whey hydrolyzate, which is a lot more expensive than the other whey types. In addition, hydrolyzate has a slightly more bitter taste.

Whey concentrate Whey isolate Whey hydrolyzate
Biological Value: 110-125 Biological Value: 125-140 Biological Value: 150
+ Unprocessed, making the healthiest whey variant
+ The cheapest whey variant
+ Processed, resulting in the purest whey variant (≈ 90%)
+ Useful with a strict ‘cut’ diet
+ May be suitable for (slight) lactose intolerance
+ Pre-digested, making the ‘fastest’ whey variant
+ More soluble than isolate and concentrate
– The least pure whey variant (≈ 80 %)
– Not suitable for lactose intolerance
– Processed, making something less healthy than concentrate
– More expensive than whey concentrate
– The most expensive whey variant, but not the purest (85-90%)
– Taste can be bitter


But how much purer is such an isolate actually? And how much difference does that make in calories? Let’s compare concentrate and isolate from the same brand: Perfect Whey Protein from Body&Fit and Whey Isolate from XXL Nutrition. (For the record, their popular Whey Delicious is a blend, not a concentrate). Keep in mind that the actual nutritional values ​​always differ slightly from the label.

Perfect Whey Protein states the following nutritional values ​​per 100 g on the label:

  • energy: 400.31 kcal
  • protein: 78.5 g
  • fat: 6.3 g (of which 4.5 g saturated fat)
  • carbohydrates: 7.4 g (of which 6.9 g sugar)
  • fiber: 1.5 g

The price per 750 g is € 14.95 (which is converted € 19.93 per 1000 g).

Whey Isolate contains the following per 100 g:

  • energy: 367.02 kcal
  • protein: 89.2 g
  • fat: 1 g (of which 0.4 g saturated fat)
  • carbohydrates: 2.5 g (of which 1.8 g sugar)
  • fiber: 0.8 g

The price per 1000 g is € 24.95.

You can see that the difference in calories is small (about 33 kcal). But on the other hand, isolate offers almost 11 g more protein per 100 g. And therefore less sugars and fats. It is up to you whether you have the money for that. In this case, you will spend 5 euros more on isolate than on concentrate.

Perfect Whey Protein /100 g Whey Isolate /100 g
energy: 400.31 kcal
protein: 78.5 g
fat: 6.3 g
carbohydrates: 7.4 g
fiber: 1.5 g
price: € 2.00
energy: 367.02 kcal
protein: 89.2 g
fat: 1 g
carbohydrates: 2.5 g
fiber: 0.8 g
price: € 2.50


We already saw that whey supplements are an ideal tool to meet your daily ‘protein quota’ (about 1,6 g/kg/d) in a clean way. In most cases, the cheaper concentrate (or a blend, which usually contains mainly concentrate) is sufficient, which gives you a lot of protein for your money with an average of 80% crude protein.

When should you opt for the slightly more expensive isolate?


We sometimes consciously choose isolate when we are cutting. As you know, you should continue to eat at least as much protein while cutting as during bulking. Maybe even more. You should therefore cut back on carbohydrates, and to a lesser extent on fats. A protein supplement that is as pure as possible helps you to meet your protein needs without also ingesting unwanted carbohydrates (sugars) and fats.

Now this is typical for the picky among us. And if you ‘re bulking, a whey concentrate (or a blend) will suffice anyway.


Another reason to choose isolate is if you have some lactose intolerance.

Whey, like most dairy products, contains lactose. Lactose is a sugar that occurs in the milk of mammals and is therefore also called milk sugar. If you are lactose intolerant, you cannot or cannot tolerate lactose completely. Although we only speak of lactose intolerance if it causes complaints when using the recommended amounts of milk (products).

Bodybuilders may experience complaints faster due to their higher protein intake. Protein supplements almost always contain lactose. Also in whey isolate, but significantly less than in concentrate. So if you’re lactose intolerant, you might want to try a whey isolate instead of a concentrate or blend.

If you have a high lactose intolerance, you can always turn to a completely lactose-free protein supplement. Think egg protein, beef protein and pea protein. These proteins all have a complete amino acid profile and good biological value. In short, they are full-fledged substitutes for milk protein.


1.    There are different types of whey, but the differences between them are so small that the choice of a particular type is only a detail in your overall approach to improving your body composition.

2.    Whey isolate is the purest form of whey. Whey isolate powders therefore have the highest protein content and the lowest proportion of carbohydrates and fats. They also contain less lactose, but are not completely lactose-free.

3.    Whey isolate is a good option if you are cutting and on a strict diet. In terms of calories, the difference with whey concentrate is not great, but the composition is just a bit more favorable (less sugars and fats). In that respect you can label isolate as ‘better’ than concentrate.

4.    Whey isolate is also an option for people with some lactose intolerance, although the isolate is not completely lactose-free either.

5.    Whey isolate is usually a bit more expensive than whey concentrate. And concentrate is less processed, which makes it slightly healthier.

6.    While strictly speaking whey protein has the most beneficial properties for muscle growth, most other animal proteins are just as good for meeting the daily protein requirement. Since whey protein powders do not contain any other valuable nutrients, it is recommended to use mainly whole protein sources and, for example, only take protein powders immediately after training.

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