The ultimate Whey Protein Guide

How is Whey Protein produced?
How is Whey Protein produced?

Whey Protein is popular with athletes/athletes, fitness enthusiasts and nutritionists due to its ability to support muscle growth and fat loss. It is also one of the most sold and aggressively advertised supplements in the fitness industry.

Whey protein based on whey, however, also offers other health benefits (e. g., by modulating the immune system and improving intestinal health), which is why it is worth taking a closer look at for those whose primary goal is not to grow big and strong.

Learn everything there is to know about the popular protein in our ultimate Whey Protein Guide.

The ultimate Whey Protein Guide for muscle building & health

What is Whey Protein?

The term “whey protein” (or simply “whey”) is used to describe a particular type of milk protein obtained from whey (which is why one often reads “whey protein”). Whey is a by-product of the production of cheese after the milk has been coagulated.

What is Whey Protein?
What is Whey Protein?

This means that Whey protein does not only contain a certain spectrum of amino acids, but also contains a variety of other substances and factors, such as beta-lactoglobulin (65%), alpha-lactalbumin (25%), bovine serum albumin (8%) and small amounts of immunoglobulin, lactose (milk sugar) and fat.

How is Whey Protein produced?

For a long time there has been no market for whey, which falls off as a by-product in cheese production, which is why there has often been talk of a “waste product”. However, these days are long gone – nowadays whey protein, which is intended for the supplement market, is mainly produced directly from milk (but it continues to be produced during cheese production).

The whey is first separated from the milk by filtration processes. This produces a liquid whey product. It is then pasteurised (heated) using a specific form of pasteurisation (“HTST pasteurisation” at high temperature for a short period of time), where the whey is heated to over 70°C for about 15 seconds to kill bacteria.

The proteins contained in the whey must then be isolated from the liquid product. This is achieved by special filter processes (mechanical filtration and/or ion exchange).

Ion exchange filtration: In this filtration process, acids (e. g. hydrochloride) or bases (e. g. sodium hydroxide) are used, whereby the proteins can also be denatured.

This method offers the advantage that it is very cheap and often leads to a better “yield” in the isolation of amino acids. The disadvantage is that many of the accompanying substances in whey (e. g. lactoferrin and immunoglobulins) are lost.

Mechanical filtration: This method is also known as cross filtration. It is a mechanical process, the application of which often leads to a higher quality product – therefore, this technology is more labor-intensive and therefore more expensive.

In the production of whey protein, it basically depends on the size of the filter and the frequency of filtration. Depending on the desired product or “degree of purity”. Each additional filtration reduces the content of lactose, fat, ash and other small impurities in the protein. A whey that undergoes fewer filtration processes (e. g. Whey concentrate) therefore contains more carbohydrates (lactose) and fat than one that passes through these processes more frequently (e. g. whey isolate).

Whey protein types: Which ones are there?

Whey protein types: Which ones are there?
Whey protein types: Which ones are there?

Currently there are 3 types of Whey Protein commercially available: Whey Concentrate, Whey Isolate and Whey Hydrolysate.

But what is the difference between these whey protein species?

Whey Concentrate

Whey concentrates usually have a protein content of 25-89%, with the majority of available concentrates having a protein content of 80%. They typically contain larger amounts (4-8%) of carbohydrates (lactose), fat and other minerals.

Whey concentrates are the cheapest form of protein powder and the raw material is often also used in protein-rich foods or snacks, such as protein bars and cake.

whey isolate

Whey isolates are considered to be purer forms of protein powder. They have a protein content of 90 – 95%, contain small amounts of carbohydrates (lactose, 0.5 – 1.0%) as well as small amounts of fat (0.5 – 1.0%) and are therefore also lower in calories than Whey concentrates.

This makes it an excellent source of protein for people who have problems digesting lactose or for those currently on a (competitive) diet.

In contrast to Whey concentrates, however, isolates also contain smaller amounts of other beneficial concomitants (e. g. immunoglobulins), which can have a positive effect on health. Those who choose an isolate for their protein powder will miss these aspects.

Whey hydrolysate

The latest development in the market for protein powders is Whey Hydrolysates (also known as “hydrolysed whey”). This form of protein powder is treated enzymatically so that the proteins contained in it, which are made up of amino acid chains, are broken down into smaller compounds (di- and tripeptides). This is intended to improve digestibility and reduce allergenic potential. This is also the reason why Whey Protein Hydrolysates are often used in infant formula and medical nutrition products.

Because of the free amino acids, white hydrolysates have a bitter taste of their own. Due to the more complex production process, these types of protein are also considerably more expensive than concentrates and isolates.

Supplementary companies praise Whey Protein Hydrolysate as the “king class” of protein powders. The protein should be absorbed even faster than in concentrates and isolates. However, this claim is not really substantiated by studies, so this sales argument simply does not apply (see Lyle’s article for a more detailed discussion).

What are the benefits of Whey Protein?

Whey proteins are particularly popular in the sports community (fitness, weight training, bodybuilding) as they have a reputation for improving physical performance by supporting muscle growth and improving body composition, as they are rich in essential amino acids (EAAs) and therefore have a high biological value.

It has also been shown that supplementation with whey protein is able to reduce oxidative stress by improving endogenous glutathione production (glutathione is the body’s strongest antioxidant). Whey Protein also has a positive effect on impaired, workout-associated intestinal function.

Much of the research on the health effects of whey protein has been carried out on protein powders, but there is a good chance that whole foods containing whey (e. g. milk and dairy products) are at least equivalent or even superior to whey protein in terms of their effects. The big advantage of Whey is the easy digestibility and purity of the powder.

In the following sections we will go into more detail about certain benefits associated with whey protein consumption.

Improvement of physical strength and muscle growth

Improvement of physical strength and muscle growth
Improvement of physical strength and muscle growth

The degree of muscle development plays a major role in performance. More musculature can usually be equated with a higher level of performance (force = mass x acceleration), so the increase of muscle mass is the easiest (and most reliable) way for athletes to increase performance.

In order for muscles to grow, they needed a sufficient stimulus, which is provided, for example, by demanding resistance training. However, hypertrophy can only be achieved if the diet (calorie and protein intake) is correct, so that protein synthesis (MPS) exceeds the protein degradation rate (MPB) over longer periods of time (a detailed discussion about how strength training and protein work synergistically to increase muscle mass is available in our members area).

One of the main concepts within the literature on muscle hypertrophy is the idea of the (positive) net protein balance (NBIL), where the NBIL is defined as muscle protein synthesis (MPS) minus muscle protein degradation rate (MPB) (i. e. NBIL = MPS – MPB). As a result, muscle cross-sectional growth occurs when the MPS is larger than the MPB.

Amino acids are a critical factor in influencing muscle protein synthesis and degradation rates. Because Whey Protein is a high quality protein source with high biological value, Whey Protein is well suited for muscle and strength building. The study situation, which dealt with this topic extensively, is correspondingly large.

Currently, the assumption is supported that supplementation of whey protein is able to support the build-up of strength and musculature. It is believed that whey protein is particularly efficient in triggering the anabolic pathway (using mTOR).

Whey Protein & Glutathione

Oxidative stress is characterized by a dysbalance of the body’s own anti-oxidative defence systems and the production of reactive oxygen species (ROS aka free radicals). During physical exertion (training) the oxygen intake can increase hundreds of times (compared to rest) and thus the production of free radicals, which lead to oxidative stress.

The current study situation is not clear, but there are indications that heavy training leads to increased production of free radicals and cellular damage. Athletes and intensely exercising athletes are thus exposed to a higher degree of oxidative stress than people who do not exercise (and are therefore less exposed to pro-oxidative processes). The body’s own anti-oxidative system must stop the increased ROS production in order to restore balance.

This is where glutathione comes into play. This is a widespread and important antioxidant which is formed from three amino acids (L-cysteine, L-glutamic acid and L-glycine). Glutathione is the most important redox substance and plays an important role in the anti-oxidative defence, nutrient metabolism and regulation of essential signalling pathways responsible for homeostasis in the body. In addition, glutathin plays a regulatory role in the activation of circulating agents of the immune system, the lymphocytes.

This shows that glutathione is a critical factor when it comes to maintaining health. Glutathione deficiency is associated with a variety of pathological conditions such as cancer, neurodegenerative diseases, cystic fibrosis, HIV and aging. Glutathione is of particular interest to athletes and intensely exercising persons, as the body’s own levels can fluctuate greatly as a result of nutrient bottlenecks, training and oxidative stress.

The high physical demands of athletes lead to high physiological stress and glutathione plays an important role in maintaining normal redox status during training. It is known that the glutathione concentration decreases due to exhausting training.

This may be an indicator that athletes do well when they support the body’s own glutathione production. In fact, scientists have shown that the amino acid cysteine is a limiting factor in the production of glutathione. So, by relying more heavily on cysteine protein sources, you can ensure that the body is able to synthesize sufficient amounts of glutathione.

Of course, it would be possible to come up with the idea and supplement it directly with cysteine, but it looks as though this is less effective, since the amino acid spontaneously oxidizes and can also be toxic. In contrast, cysteine containing foods containing cystine (two cysteine molecules held together by a sulphur compound) are more stable than free cysteine and have the advantage of being digested and ingested without any problems. Whey protein, such as whey concentrate and whey isolate, are excellent protein sources with a high cysteine content. In addition, it is absorbed by the usual (non-hazardous) metabolic pathways.

By taking Whey Protein Supplements rich in cysteine, it is possible to prevent the workout-related decrease in glutathione concentration without harmful side effects, so the supplement could support the body’s own production of glutathione and reduce oxidative stress. This fact has been extensively researched by scientists: supplementation with Whey Protein is suitable in principle to keep glutathione concentration in the body at a normal level for athletes and non-athletes.

Whey Protein has also been shown to help athletes cope better with oxidative stress and to be a safe, effective and alternative source of antioxidants that can help prevent injuries and illnesses caused by excess production of free radicals (ROS).

To cut a long story short: The current state of research supports the assumption that Whey Protein Supplements can support glutathione status in athletes and support the endogenous anti-oxidative system.

Whey protein & immune function

Demanding and heavy training is associated with impaired function of immune cells. Insufficient supply of nutrients (e. g. in the diet) can additionally increase the negative influence of physical exertion and worsen immune competence. As a result, suppression of immune function increases the risk of infection.

In the context of training periodization, volume and intensity vary in certain phases of the season, which can sometimes lead to overload (overreaching and/or over-training). Here too, the immune function can react sensitively to an increase in intensity/volume. And although research has not yet shown that athletes are clinically impaired in moments of impaired immune function, this may still be sufficient to carry a higher risk of infection.

As you may already know, the immune system relies heavily on amino acids, so endogenous amino acids supplied by food can affect the state of the immune system. Compared to other protein sources, Whey Protein seems to have a unique ability to strengthen immunity due to its ingredients. These positive substances include? -lactalbumin,? -lactoglobulin, lower serum protein fractions, lactoferrin and a number of immunoglobulins.

Note: As already mentioned above, these factors are usually contained in Whey concentrates, but not in Whey Isolates (because of the filtering processes). From a health perspective, a Whey concentrate can be the better choice in this case.

Whey Protein & Gut Health

Intensive training leads to a reduction in organ perfusion, reduced blood flow to the gastrointestinal tract and an increase in temperature. Such a combination can lead to a dysfunction of the intestinal barrier due to a higher permeability of the “tight junctions”.

The increased permeability of the intestinal walls can lead to an increased invasion of gram-negative bacteria and/or toxic components, which find their way into the bloodstream. So-called “endotoxins” are highly toxic lipopolysaccharides (LPS) from the outer cell walls of gram-negative bacteria and are able to induce a large number of immune reactions in vivo (via induction of the cytokine network).

This process, also known as endotoxemia, can lead to an increased susceptibility to infections and autoimmune diseases that occur as a result of the inclusion of pathogens/poisons in tissue and blood circulation.

The field of research on intestinal health and intestinal permeability is still relatively new, so long-term prospective studies need to clarify the consequences associated with chronic permeability at a low level. However, recent research has shown that there is a relationship between intestinal permeability and a variety of autoimmune diseases (Crohn’s disease, Hashimoto’s disease, lupus, psoriasis and rheumatoid arthritis).

There are also indications that there is a link between intestinal permeability and mental disorders (e. g. schizophrenia and depression).

As mentioned above, tight junctions are the main component of intestinal barrier function – they serve as a physical and functional barrier that protects us from macromolecules in the lumen penetrating into the body. For this reason, the regulation of the permeability of the trailing ridges is a critical factor in maintaining intestinal integrity and reducing endotoxin exposure.

The amino acid glutamine plays an important role in this context, as it is responsible for maintaining the integrity of the final bars. It is also the most abundant amino acid in the blood and is considered “semi-essential”. This means that under normal conditions, sufficient glutamine can be produced by the body to ensure normal physiological function. However, if situations involving high stress (training, injuries) are added, the body’s own glutamine production may no longer be sufficient, so that the body is dependent on an exogenous supply of glutamine (e. g. via food) to cover its needs.

It has been shown that intestinal permeability via glutamine supplementation can be improved by restoring the integrity of the trailing ridges, which have been disrupted by a variety of physiological stressors, through certain molecular mechanisms. Furthermore, it has been demonstrated that glutamine is able to reduce workout-induced intestinal permeability.

Whey protein contains larger amounts of glutamine and scientists have demonstrated that supplementation is able to reduce intestinal permeability. This means that supplementation with Whey Protein could help to reduce intestinal (training induced) permeability, prevent endotoxemia and reduce the risk of autoimmune diseases/reactions.


Whey Protein is an excellent source of a variety of amino acids and nutrients that have beneficial effects on performance and health. In combination with demanding training, Whey Protein not only increases the amount of lean mass and strength, but also supports the body’s own glutathione production, modulates the immune system and improves intestinal health.

Finally, Whey Protein is not a substitute for a balanced, protein-rich diet. However, a good whey can still be a useful supplement for people who are aware of sports, nutrition and health.

Whey Protein: When and how to use it?

Whey Protein: When and how to use it?
Whey Protein: When and how to use it?

In fact, there are no clear guidelines on how and when to use whey protein, as it is basically a food product such as cheese or yoghurt. However, there are some aspects and considerations that may make sense when using Whey.

In practice, whey protein is often consumed in the form of a post-workout shake, as this type of protein is rapidly absorbed and is able to stimulate protein synthesis. Recent findings, however, support the assumption that a combination of fast and slow protein (e. g. milk protein consisting of casein and whey or casein + whey) can be useful, as it also reduces the breakdown of muscle protein – see this article (or this article and Lyle’s contribution to a more intensive discussion).

Depending on gender, size, weight and age, the intake should be between 20-40g protein to maximize the positive (anabolic and anti-catabolic effects of Whey Protein. You can mix it either in water (no additional calories) or in low-fat milk (a few extra calories) in a shaker or, for example, in a blender with frozen fruit/fruit to make a delicious smoothie.

Protein shakes and whey powder are also ideal for optimizing low-protein meals (e. g. the morning porridge). Some people also use them as low-calorie (saturating) snacks or snacks.

Whey Protein & Side Effects

Consuming whey protein can also cause some complications. Known side effects include constipation, skin blemishes, flatulence and bloating, but these do not always occur in every person.

Persons who are allergic to milk (e. g. because of intolerance to protein or lactose intolerance) should consult their doctor before supplementing or should opt for a milk-free alternative (e. g. rice protein or pea protein).

Foods containing whey protein

Whey is usually found in milk. It is therefore no wonder that various dairy products, including cheese, butter and yoghurt contain certain amounts of whey protein. Have you ever opened a yogurt and noticed a milky liquid on the surface? Yep – that’s Whey!

Whey is also used as a versatile ingredient in the food industry, e. g. as an emulsifier in bakery products, ice cream mixtures and dressings. It is used in infant formula, frozen desserts and soups/sauces to improve solubility. The amounts contained in it are not so large now, but at least they are contained (and it is known that this can’t hurt).

Whey Protein Vs. other protein sources

The quality of proteins is determined by various indicators, including biological valence (BV) and a special amino acid score for protein digestibility (PDCAAS).

Biological valence refers to a practical measurement based on the ability to use protein in animals and humans. In simple terms, we analyse how much nitrogen is retained / absorbed in the body after consumption of the protein source.

The PDCAAS value is between 0 and 1 and the quality of the protein is determined by measuring the amino acid content in relation to human needs. Basically, this means that the higher the BV and PDCAAS value of a protein, the more efficiently it can be used by the body.

Below you will find a table containing both values for different proteins (as well as whey):

of proteinBiological valuePDCAAS
Whey concentrate & isolate791.0
whole egg1001.0
egg white881.0
Grained cream cheese841.0

Frequently Asked Questions (F. A. Q.) about Whey Protein

How much Whey Protein should I use?

As I said before, there is no real guideline on how much Whey Protein you can use during the day. However, there are some aspects that you should keep in mind when using it. For a maximum effect (stimulation of protein synthesis) an intake of 20-40g whey protein should be aimed at.

The rule of thumb applies: older male trainers, who are also relatively heavy, should rather be placed at the upper end of the spectrum, while younger persons of female gender with little weight tend to find themselves at the lower end of the spectrum.

Most Whey Protein users use protein powder as a post-workout shake either in the morning and/or immediately after training.

Taking the Whey 1-2 times a day in order to optimize your protein intake (if you have problems covering it with conventional food) makes the most sense. Otherwise, it is sufficient if you take it around your workout (e. g. taking it every 2 days if you train on every other day).

I’m lactose intolerant. Can I still use Whey Protein?

There are anecdotal reports from people who report varying degrees of digestive problems due to whey consumption. As a rule, Whey Isolate has the lowest lactose content – this also reduces the risk of gastrointestinal problems, so that many people with lactose intolerance can cope well with isolate.

If you belong to a group of people who suffer from digestive problems even with an isolate, you should probably switch to a protein that is not based on milk (e. g. rice and pea protein) or supplemented with lactase.

I’m allergic to milk. Is Whey Protein safe for me?

The severity of allergic reactions is highly individual, and if you are allergic to milk protein, you may easily cope with whey hydrolysate or a very pure whey isolate (since many of the allergens are filtered out during the filtration process).

If you are lactose intolerant, it may be sufficient to rely on an isolate, as it usually contains small amounts of lactose. In any case, it would make sense if you consult your doctor before eating or start with small amounts to find out how your body reacts to whey.

Is it true that Whey protein is bad for the kidneys and/or bones?

If you are in good health and have two functioning kidneys, there is no reason to believe that Whey (or any other protein-rich food) will cause measurable damage to the kidneys.

There are allegations that protein-rich foods are bad for bone health because they allegedly cause calcium depletion. The truth is (like so often) different: The opposite is true. Protein-rich diets improve calcium uptake in the digestive tract and thus help to strengthen the bone skeleton, which is particularly important for women and elderly people (anti-osteoporosis)

Those individuals who ingest too little protein through food are even at risk of weakening the bone skeleton (64) if they further limit protein intake.

For a detailed discussion of this topic (and the study situation), see the article “Protein-rich nutrition | Bad for kidneys & bones?”.

Can I combine Whey Protein with other powdered supplements (e. g. glutamine, creatine)?

Definitely! There is absolutely no reason why you should not mix your Whey Protein with other powder supplements such as creatine or glutamine (although an additional supplement with glutamine might be a slight overkill considering that whey already contains larger amounts of it).

It is also possible to enrich your Whey with greens or similar to increase the micronutrient content.

Does it matter which liquid I mix the whey protein with?

The consistency of the shakes changes depending on the liquid you mix. As a rule, the protein shake becomes very fluid with water, while the combination with milk leads to more viscous shakes.

If you look at the whole thing from the perspective of intake, there are some arguments in favour of mixing your shake with low-fat milk (or a source of carbohydrate) and/or salt, as this could additionally improve the intake / anabolic effect. In most cases, however, these effects would not be noticeable.

Does boiling/baking lead to denaturation of the protein?

Yes, the cooking and baking process can lead to denaturing of the whey. However, this does not affect the powder’s ability to build muscle and strength, as the effect of the whey is primarily due to the amino acids it contains.

Although the denaturation process can impair the bioactivity of individual whey constituents, this is not an aspect that should greatly affect the brain.

Are there any dangers associated with taking Whey Protein?

As with all foods with a certain allergenic potential, whey (a milk-based protein) can also develop allergic reactions. In other words, there are people who are allergic to milk proteins (and whey).

At the same time, you should pay attention to certain quality criteria when choosing your protein and focus primarily on manufacturers who guarantee good quality control. Whey protein is basically a foodstuff like many others, so the quality can be affected by improper production. However, it is by no means the case that the dangers outweigh the potential benefits, i. e. in most cases nothing at all will happen at this level.

Is Whey Protein Safe for Teenagers?

Based on the current state of knowledge (and there really are countless studies out there that have studied the effects of Whey in more detail), there is no reason to believe that Whey Protein is harmful to adolescents and teenagers. On the contrary, it contains many beneficial substances that can support the growth process.

Should women use other Whey Protein products than men?

No, there is no good reason why women should consume other protein powders or whey products than men – even though there has recently been an increase in the number of such products launched on the market to specifically target women.

Since women usually weigh less than men, their daily protein requirements are also smaller, which means they need less whey than men. Otherwise, however, there is not much else that changes for women in this respect.

Whey protein isolates are known to be higher in purity. Should I use Whey Isolate instead?

Whey isolates do indeed have a high degree of purity (and high protein content per serving), which makes them a good choice when the goal is muscle build-up/preservation.

However, keep in mind that the special degree of processing of the isolate also filters out a large number of bioactive substances (e. g.? -lactalbumin,? -lactalbumin, immunoglobulins, glycomacropeptides and lactoferrin). In this respect, it may be useful to use a Whey concentrate or both, isolate and concentrate.


Written by Marcus

Fitness is not always easy and there is no perfect plan for everyone to stay fit for life. That is why I have set myself the goal of finding the most accessible way for people to build healthy lifestyles.