7 Min
Zuletzt aktualisiert am 01.09.2025
What used to be thrown away as waste is now bought by active people for a lot of money. And I’m sure you’ve heard of it before! We’re talking about whey protein.
What almost sounds like a brand is actually just a certain type of protein. But what exactly is whey protein? Is whey protein really beneficial, and what are possible drawbacks? Let’s find out together over the next few minutes!
Your knowledge to go: What is whey protein?
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Whey protein is obtained as a by-product during cheese production and then processed into protein powder.
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There are different types of whey protein powders – the most well-known are whey concentrate and whey isolate.
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Advantages include the high biological value of whey protein, its complete amino acid profile, and the rapid availability of amino acids.
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Disadvantages: Not everyone tolerates whey or is a fan of it for other reasons. Alternatives include other animal-based and plant-based protein types.
Whey protein – explained
So, what is whey protein? Whey protein (in German, much less cool-sounding: Molkenprotein) is one of the main forms of protein found in milk. The other major, well-known group is casein. Whey protein is therefore naturally present in cow’s milk and dairy products.
And what, then, is whey protein powder? Easy! Whey protein is also sold as protein powder and is one of the most popular protein powders! However, not everyone is enthusiastic: there are an increasing number of critical voices, and many active people are looking into alternatives. We’ll cover that later so you can form your own opinion!
Where does whey protein powder come from?
Now, brace yourself: What sounds super fancy today used to be a waste product. Whey is obtained from a by-product of cheese production: whey. Whey is a watery liquid that forms when milk curdles – when the future cheese separates from the milk. It consists mostly of milk sugar, i.e., lactose, but also contains other nutrients such as whey protein and fats.
Some time ago, whey was considered a useless by-product and was either discarded or fed to animals.
Then technology and gyms entered our lives, and everything changed. Okay, maybe not quite that dramatically.
The food industry, however, saw potential in this liquid – specifically in the proteins it contains – and began to use them. With today’s technology, this whey protein can be easily extracted and ends up as protein powder in your shake.
Once you know what whey protein really is and how it’s made, you’ll see the product – and its often high price – in a whole new light, right?
What does whey protein do?
Now we know what whey protein is. But what does protein powder actually do? And what exactly is whey protein good for? In general, getting enough protein is important for muscle maintenance and muscle growth. However, it can often be challenging to consume enough protein in everyday life. That’s why many active people turn to protein powder to supplement their intake.
Let’s set aside the question “What is whey protein?” for a moment. Other protein-rich products like peanut butter or plant-based protein bars can also help you meet your protein needs – so you don’t necessarily need whey!
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Different types of whey
Isolate, concentrate – what now?! There are different types of whey. These mainly differ in their composition and their protein content.
Which type is best can’t be answered in general terms. Depending on your goals, preferences, and no-gos, one type may be better suited for you. Or you may find that whey simply doesn’t fit your lifestyle. But more on that later!
First, let’s take a look at the different types:
Whey protein concentrate
What is whey protein concentrate? Whey concentrate consists of about 70–80% protein, so it has a relatively high protein content. In addition to protein, it still contains some carbohydrates such as lactose, as well as fats. Concentrate is relatively simple to produce and therefore cheaper than the next two forms.
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Advantage: cheaper price
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Disadvantage: still contains lactose, so it’s not necessarily suitable for lactose-intolerant people
Whey protein isolate
Terms like ion exchange process or microfiltration alone show that the production of this form is much more complex. But it’s worth it: the protein content is significantly higher, at 85–95%, than that of concentrate. This is because, through various filtration methods, other substances such as lactose are removed from the product, leaving mainly protein.
As a result, isolate is often used in higher-priced protein powders. It’s particularly popular with people who are lactose intolerant since it contains almost no lactose.
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Advantage: almost lactose-free, therefore suitable for most lactose-intolerant individuals, very high protein content
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Disadvantage: may taste bitter
Whey protein hydrolysate
Hydrolysate has a protein content of about 80–90%, putting it roughly on par with isolate. The particularly convenient thing about this form is that the proteins are already broken down into peptides and amino acids – the small building blocks of proteins. This means they’re almost immediately available to your body. By comparison, most other proteins must first be digested, which takes time before the body can use the amino acids. Whey hydrolysate is therefore a protein source that can contribute to rapid protein supply. Many active people take hydrolysate as a protein boost directly after training.
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Advantage: high protein content, rapidly available amino acids
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Disadvantage: very expensive, often bitter taste
There’s also fermented whey protein – but that’s less relevant here.
Quality & effect
What’s so special about whey protein?
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Whey protein has a very high biological value. This value indicates how efficiently the human body can use a given protein to build body protein. One crucial factor here:
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Whey has a good amino acid profile and contains all essential amino acids (EAAs). These are amino acids that the body cannot produce itself and must therefore be obtained from food: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine, and (for infants) histidine.
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In addition, whey (especially hydrolysate) is very easily digestible, meaning the amino acids can be absorbed by your body very quickly! That’s music to the ears of active people!
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Last but not least: The protein content of the different whey types is very high, making it a good protein source in a protein-rich diet.
Now that you know what whey protein is, you’re probably wondering about its pros and cons. Here’s our overview:
Advantages of whey
Whey has numerous advantages that make it one of the most popular protein powders:
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high protein content with relatively low fat and carbohydrate content
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complete amino acid profile
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high biological value
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provides the body with quick amino acids: whey is easily digestible and thus a source of rapidly available proteins
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depending on the type: lactose-free and therefore suitable for lactose-intolerant individuals
Disadvantages of whey
Of course, whey also has some disadvantages that shouldn’t be ignored when explaining what whey protein is:
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For lactose-intolerant individuals and people who can’t tolerate milk, whey is only conditionally suitable (and in some cases not at all).
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Depending on processing and purity, many products taste bitter.
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To mask the bitterness, sweeteners or other sweetening agents are often added to make products taste better – but many people prefer to avoid such substances.
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Whey is not suitable for people following a vegan lifestyle, as it’s derived from milk.
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Independent tests have shown that the quality of whey products varies between suppliers. It’s best to choose reputable, trustworthy brands or consider alternatives.
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Whey protein powders often contain numerous additives and fillers.
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Especially for sensitive individuals such as the lactose intolerant, side effects like stomach pain may occur after consumption.
Alternatives
More and more people are also looking for alternatives to whey – for various reasons: they don’t tolerate whey, want to switch to vegan products, or simply prefer other types of protein.
Animal-based protein types:
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Casein
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Egg protein
Plant-based protein types:
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Soy protein
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Rice protein
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Pea protein
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Hemp protein
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Flaxseed protein
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…
Particularly popular among plant-based proteins are multi-component proteins, which are a mix of different protein types. The advantage? The often incomplete amino acid profile of plant-based proteins can be supplemented to form a complete amino acid profile. This way, you can also combine the benefits of various protein types.
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And don’t forget: “Real” protein-rich foods. It doesn’t always have to be powder. Foods such as legumes, meat, and fish also contain plenty of protein. So always aim for a balanced diet!
What’s the best protein type?
All the proteins mentioned here have pros and cons. Therefore, it’s impossible to say universally which protein type is best. Depending on your diet, taste, and needs, one type may be better suited for you. Just try out different types for yourself.
Conclusion: What is whey protein?
For some, it’s the best protein for muscle building; for others, it’s a red flag. Opinions on whey differ widely. And that’s okay – after all, there are so many protein types that everyone can find the right product for themselves. What’s always important, though, is to be well-informed and know what whey protein is. And after reading this article, you certainly do. That already puts you ahead of many of your gym buddies – many can only answer the question “What is whey protein?” with a shrug.
References & sources
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Newar, V. (2022). A Review on Whey Protein: Benefits, Myths and Facts. International Journal of Innovative Science and Research Technology, 7(10).
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Saba Zafar (2024). Nutritional and Functional Importance of Whey Protein in Human Health and Food Applications. Applied Agriculture Sciences, 2(1).
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Shankar, J. R. & Bansal, G. K. (2013). A Study on Health Benefits of Whey Proteins. International Journal of Advanced Biotechnology and Research, 4(1).
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Verbraucherzentrale (2025). Whey-Protein: Das sollten Sie über Molkenprotein wissen. https://www.verbraucherzentrale.de
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Do you have questions? Then feel free to send me an email – I look forward to hearing from you! :)
The information shared in this article does not replace individual medical or nutritional advice.
