Protein supplements

The sight of people vigorously stirring protein shakes in gym locker rooms has become commonplace. However, this raises questions: are protein supplements really necessary? Do they actually speed up muscle building? Or maybe it’s just a marketing gimmick? This article aims to provide a comprehensive, evidence-based guide to the world of protein supplements in the context of strength training. We will dispel myths, present facts and help you understand how to use the potential of protein wisely.

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The Power of Protein in Your Gym Workout

Protein is a fundamental macronutrient, essential for every body, and its importance increases in physically active people. Although mainly associated with muscle building, it plays a much broader role – it is crucial for the proper functioning of the immune system, the production of hormones and enzymes, oxygen transport and many other metabolic processes. Understanding these basic functions is the first step to appreciating the role of protein in an athlete’s diet.

The popularity of supplements in the world of strength training is undeniable. However, the multitude of products available and often contradictory information can be overwhelming. That is why it is so important to base your choices on reliable knowledge, and not only on the promises of manufacturers. This guide will provide you with the tools to make informed decisions about protein supplementation.

Protein Supplements: What Are They and Why Should You Consider Them?

Protein Definition and Its Role

Proteins are complex molecules made up of smaller units called amino acids. They can be compared to the building blocks from which the body builds and repairs its structures. There are twenty different amino acids, some of which the body can synthesize on its own (endogenous amino acids), and some of which must be supplied with food (essential amino acids, including BCAAs).

The functions of protein in the body are extremely diverse and crucial for life:

Tissue Construction and Repair: Protein is the basic building block of muscles, skin, hair, nails and internal organs. It is responsible for the regeneration of damaged cells, wound healing and the growth of the body.
Regulation of life processes: Many enzymes (catalyzing chemical reactions) and hormones (e.g., insulin, thyroid hormones) are proteins. Proteins also participate in the immune response as antibodies.
The transport and storage of protein powder are crucial to maintain its quality. Proteins, like hemoglobin, transport oxygen in the blood. Others transport vitamins, minerals or fats.
Maintaining balance: Proteins help maintain the acid-base and water balance of the body.
Energy Source: In situations of deficiency of other energy sources (carbohydrates, fats), the body can use proteins for energy purposes, although this is not their primary function.
Satiety and Thermogenesis: Protein is more filling than carbohydrates and fats, which helps control appetite. Its digestion also requires a higher energy expenditure (thermic effect of food), which can support weight control.

What are protein supplements?

Protein supplements are concentrated sources of protein, usually in powder form, obtained from various raw materials, such as milk (whey, casein), eggs, soybeans or other plants (peas, rice, hemp). Their main purpose is to conveniently supplement the diet with protein, especially when the demand is increased or it is difficult to cover it with food alone. These are not magical substances, but only processed food that provides one key macronutrient in an easily digestible form.

Increased Protein Demand in Active People

Intense physical exertion, especially strength training, leads to micro-damage to muscle fibers and increased protein breakdown (catabolism). In order for muscles to regenerate, repair and adapt to loads (i.e. grow and become stronger – anabolism), they need the right amount of “building blocks” – amino acids supplied from protein.

Therefore, the protein requirement in physically active people is higher than in people with a sedentary lifestyle. While for the general population it is recommended to consume about 0.8 g of protein per kilogram of body weight per day, in people who strength train these values increase to 1.4-2.2 g/kg of body weight. Some sources suggest up to 2.5 g/kg of body weight during periods of intense muscle mass building.

Insufficient supply of protein in an athlete’s diet can lead to negative consequences: hindered regeneration, increased risk of injury, weakening of strength and muscle mass (advantage of catabolism over anabolism), and even reduced immunity.

When to consider supplementation?

The basis of the diet should always be balanced, varied food. Protein supplements come into play as a supplement, not a replacement for a diet. It is worth considering them when:

It is difficult to cover the demand with diet alone: Achieving 1.6-2.2 g of protein/kg of body weight only from food can be a logistical challenge (time to prepare meals), appetite (the need to eat large volumes of food) or caloric (some protein sources are also rich in fats).
You need convenience: A protein shake is a quick and easy way to provide a portion of protein, e.g. after training, on the go, or as an addition to a meal.
There are dietary restrictions: Vegans and vegetarians may find it difficult to get enough complete protein; Plant-based supplements can be a valuable support. People with lactose intolerance can choose isolates, hydrolysates or non-dairy proteins.
Support for specific goals: During periods of building muscle mass or reducing body fat (where protein helps protect muscles and increases fullness), supplementation can make it easier to achieve your goals.

Understanding why athletes turn to nutritional supplements goes beyond just physical activity. The key factor is often the difference between the increased physiological demand resulting from training stress and what can realistically be provided with the diet. Training intensifies the turnover of proteins in the body, and covering higher needs (e.g. 1.6-2.2 g/kg) only with food can be logistically or calorically difficult. Supplements offer a concentrated, easy-to-consume source of protein , becoming a practical tool to fill this gap and meet elevated demands that diet alone may not sufficiently cover.

Guide to Protein Powder Types: Choose Wisely

The protein supplements market offers a wide range of products, differing in the source of protein, the degree of its processing, the content of additional ingredients (such as lactose or fats), the speed of absorption and the amino acid profile. Understanding these differences is crucial to choosing the product best suited to your individual needs. Proteins can be divided into concentrates (less processed, lower protein content, more additives), isolates (more purified, higher protein content, fewer additives) and hydrolysates (pre-digested, fastest absorption).

Whey protein: the king of supplements?

Whey protein is the most popular type of protein supplement, valued for its high quality and effectiveness. It is produced as a by-product of the production of cheese from cow’s milk. It comes in three main forms:

WPC (Whey Protein Concentrate):
- Characteristics: It usually contains 70-80% protein, some amounts of lactose and fat. It has a good, milky taste and is the cheapest option. It is absorbed more slowly than isolate or hydrolysate, but faster than casein.
- Use: A good choice for beginners looking for an economical solution to supplement protein in their diet in general.
- Examples of brands: Trec Nutrition Whey 100 , 6PAK Milky Shake Whey , Olimp Whey Protein Complex , Promaker Gold WPC 80 , OstroVit WPC 80 , Formotiva WPC.
WPI (Whey Protein Isolate):
- Characteristics: It contains 90% or more protein, with minimal lactose and fat (often less than 1g per serving). It is formed by further filtration of the concentrate. It absorbs faster than WPC.
- Use: Ideal after training for a quick supply of amino acids, for people with lactose intolerance, during periods of fat reduction (low carbohydrate and fat content). It is more expensive than WPC.
- Examples of brands: 7Nutrition Whey Isolate 90 , BioTechUSA Iso Whey Zero , Olimp Pure Whey Isolate 95 , OstroVit WPI 90.
WPH (Whey Protein Hydrolysate):
- Characteristics: Whey protein (usually isolate) subjected to the process of hydrolysis, i.e. initial enzymatic digestion. Protein molecules are broken down into shorter peptides and free amino acids. It provides the fastest absorption (even in 15-30 minutes). It can contain up to 99-100% protein. It is usually lactose-free and a source of pure protein.
- Use: Mainly for advanced athletes looking for the fastest post-workout recovery, potentially easier to digest for people with digestive problems. It is the most expensive form of whey protein, sometimes with a slightly bitter taste.
- Examples of brands: Optimum Nutrition Platinum Hydrowhey.
Amino acid profile: Whey protein is a complete protein, which means that it contains all the essential amino acids. It is distinguished by a particularly high content of branched-chain amino acids (BCAAs), especially leucine, which is a key amino acid initiating muscle protein synthesis (MPS).
Advantages: Fast absorption (especially WPI and WPH), high BCAA/leucine content, proven effectiveness in supporting muscle growth and regeneration, high biological value of protein preparations.
Disadvantages: WPC contains lactose, which can cause problems in people with intolerance. WPI and WPH are more expensive. It can cause allergic reactions in people who are allergic to cow’s milk proteins.

Micellar Casein: Protein for Long Hours

Source: protein supplements in the store. The main type of protein found in milk (about 80%).
Properties: A characteristic feature of casein is its slow digestion and absorption. In the acidic environment of the stomach, it forms a kind of gel, which slows down the process of releasing amino acids into the bloodstream. This ensures a long-lasting, stable supply of amino acids for many hours.
Amino acid profile: Casein is a complete protein, but it contains less BCAAs, especially leucine, compared to whey. It contains other bioactive peptides that may have beneficial effects on the immune and digestive systems.
Use: Due to its slow release of amino acids, casein is an ideal choice for the night to minimize muscle catabolism (protein breakdown) during sleep. It can also be used throughout the day, between meals, to ensure a constant supply of amino acids and increase the feeling of satiety.
Advantages: Slow, long-lasting release of amino acids, anti-catabolic effect, increases the feeling of satiety.
Disadvantages: Slow absorption makes it less optimal immediately after a workout when a quick boost of amino acids is needed. Lower BCAA/leucine content than whey. Contains lactose and milk allergens.

Soy Protein: Plant-Based Alternative & Facts

Source: Soybeans.
Properties: It is one of the few complete plant proteins, which means that it provides all the essential amino acids. It is absorbed at an intermediate rate – faster than casein, but slower than whey. Often available in isolate (SPI) form, which is low in fat and carbs.
Amino acid profile: Good amino acid profile, although usually with a lower leucine content than whey protein. It contains isoflavones, which are phytoestrogens (plant compounds with estrogen-like effects).
Use: An excellent option for vegetarians, vegans and people with lactose intolerance. It may support the building of muscle mass, although it may require slightly higher doses than whey to achieve similar MPS stimulation. Research suggests potential health benefits, such as lowering LDL cholesterol and supporting bone health.
Advantages: Complete plant-based, lactose-free protein, potential health benefits, contains antioxidants and protein for muscle support. , good BCAA content for a vegetable protein.
Disadvantages: It may stimulate MPS less well than whey at the same dose (due to lower leucine). It is a potential allergen. There are concerns (albeit often based on myths) about the effects of phytoestrogens on men’s hormonal balance – more on this in the myths section. It may have a specific taste for some people. It can interfere with the absorption of thyroid medications.
Examples of brands: TREC NUTRITION Soy Protein Isolate.

Other vegetable proteins (peas, rice, hemp, mixes): the power of nature

Origin: Peas, rice (usually brown), hemp, pumpkin seeds, sunflower, etc. They are very often found in the form of mixtures to obtain a complete amino acid profile.
Properties: They are 100% vegan, lactose-free. Pea protein is often considered hypoallergenic. The absorption rate varies, but generally slower than that of whey protein.
Amino acid profile: Single plant sources are often incomplete – they lack one or more essential amino acids (e.g. rice has little lysine, peas – methionine). Good mixtures (e.g. peas + rice) supplement these deficiencies, creating a complete protein. The leucine content is usually lower than in whey, which may mean that a larger portion (e.g. 25-30g instead of 20g of whey) needs to be consumed for a similar anabolic effect. Hemp protein is one of the most interesting sources.
Use: A basic choice for vegans, vegetarians and people with allergies to milk or soy proteins. A good way to diversify the sources of protein in your diet.
Advantages: Suitable for diets that exclude animal products and allergens (milk, soy), they often contain additional nutrients such as fiber, vitamins, minerals, hypoallergenic options, choosing a more environmentally sustainable choice.
Examples of brands: BioTechUSA Vegan Protein, MyProtein Vegan Protein Blend, ALLNUTRITION Vegan Protein, is an example of plant-based protein for muscle support. , Intenson Hemp Protein, Solve Labs Complete Plant Based Protein.
Disadvantages: Single sources often have an incomplete amino acid profile. Lower leucine content. Potentially lower bioavailability and digestibility of some sources. They can be more expensive than WPC. They sometimes have an earthy or slightly “sandy” flavor/texture, which can be noticeable in protein powders.

Beef protein: another animal option

Source: Obtained from beef, often in the form of hydrolysate for better solubility and absorption.
Properties: It is a lactose-free alternative to milk proteins. It is characterized by a high protein content and good digestibility.
Amino acid profile: It differs from the profile of milk proteins. It is rich in amino acids such as glycine, proline, and hydroxyproline (important for connective tissue), but has a lower BCAA content compared to whey. It naturally contains creatine.
Use: A good choice for people who avoid dairy products (e.g. due to allergies, intolerances or paleo diet).
Advantages: Lactose-free, high protein content, natural creatine content.
Disadvantages: A different amino acid profile than whey (less BCAA). It can be more expensive. For some people, the taste may be less appealing than that of milk proteins.
Examples of brands: Olimp Gold Beef Pro-Tein, Bulk Beef Protein Isolate 97.

Egg Albumin: A Classic Still in Play

Source: Egg white (albumin).
Properties: It is considered a benchmark protein due to its high biological value. It is absorbed at a moderate rate – slower than whey, but faster than casein. It is naturally lactose-free.
Amino acid profile: Complete protein, with a very good amino acid profile, including a high content of BCAAs.
Use: An all-purpose protein, suitable for use at different times of the day, for those who avoid dairy.
Advantages: High quality and biological value, complete amino acid profile, lactose-free.
Disadvantages: It can be more expensive than whey. It is an allergen for people allergic to eggs. Taste and solubility may not suit all consumers.

Protein blends

Ingredients: They combine different fractions or sources of protein, e.g. WPC with WPI, whey with casein, various vegetable proteins.
Purpose: Achieving a varied rate of amino acid absorption (both fast and slow release), which theoretically is supposed to ensure a constant supply of amino acids to the muscles for a longer period of time. With plant mixes, the goal is to achieve a complete amino acid profile.
Use: They can be universal – used both after training and during the day or before bedtime, depending on the composition.
Comments: It is worth checking the proportions of individual proteins in the mixture, if the manufacturer provides them. There is no conclusive evidence that blends are clearly more effective at stimulating MPS than high-quality single sources like whey.
Examples of brands: Olimp Whey Protein Complex (WPC+WPI), Rule One R1 Protein (WPI+WPH).

The choice of a specific type of protein should not be based solely on the percentage of protein in the product. A holistic assessment is important, taking into account the interplay of the absorption rate, amino acid profile (especially leucine content), individual body tolerance (to lactose, potential allergens) and specific goals and timing of consumption (fast post-workout regeneration vs. slow release before bedtime). Different proteins are absorbed at different rates , which affects the availability of amino acids to the muscles. Leucine is a key signal to start building muscle proteins. Individual factors, such as lactose intolerance or the choice of a vegan diet, determine the available options. Goals also vary – after a workout, the priority is to provide amino acids quickly (whey preferred), while slow release (casein preferred) is more beneficial before bedtime. Therefore, the “best” protein is a relative concept and depends on the context, requiring the product characteristics to be tailored to the user’s unique situation.

The development of the market for plant-based and alternative proteins (beef, egg) reflects not only the growing dietary diversity (veganism, allergies), but also the search by consumers for specific benefits beyond standard whey. Even though whey often remains the benchmark in terms of MPS stimulation, due to its high leucine content and rapid absorption, other options are gaining popularity. The rise in popularity of plant-based diets and the prevalence of allergies and intolerances (to dairy, soy) are driving demand for alternatives such as pea, rice, hemp , beef , and egg protein. Although whey often shows a stronger anabolic response in the short term , alternatives offer specific advantages (lactose-free, hypoallergenic, different nutrient profile). This market diversification responds to the specific needs and preferences of consumers, showing that the “optimal” choice can mean different things to different people.

Comparison table of popular types of protein supplements

Protein Type: It is worth noting the differences between whey protein concentrate and isolates.	Main Source	% Protein (n.d.)	Absorption rate	Key Amino Acids	Best Applications	Advantages	Disadvantages
WPC (Whey Concentrate)	Milk whey	70-80%	Medium-Fast	High BCAA/Leucine content, complete	General protein supplement, post-workout (beginners)	Good taste, low price, high quality	Contains lactose and fat, lower % protein than WPI/WPH
WPI (Whey Isolate)	Milk whey	≥90%	Fast	Very high BCAA/Leucine content, complete	After training, for people with lactose intolerance, reduction	Very high % protein, minimal lactose/fat, fast absorption	More expensive than WPC, potential milk allergens
WPH (Whey Hydrolysate)	Milk whey	≥90% (up to 100%)	Very fast	Like WPI, but pre-digested (peptides)	Maximum regeneration after training, digestive problems	Fastest absorption, very high % protein, lactose-free	The most expensive, sometimes bitter taste, potential milk allergens
Micellar casein	Milk	80-90%	Very slow	Complete, less BCAAs than whey, bioactive peptides	Before bedtime (anti-catabolism), long breaks between meals	Slow release, anti-catabolic effect, satiety	Slow absorption (not optimal after training), contains lactose/milk allergens, less BCAA than whey
Soy Isolate	Soybeans	~90%	Average	Complete, good BCAA content (less leucine than whey)	For vegans/vegetarians, people with lactose intolerance	Complete plant-based protein, lactose-free, potential health benefits, contains antioxidants	Potential allergen, concerns about phytoestrogens (mainly myths), taste, may stimulate MPS worse than whey
Plant Mix (e.g. G+R)	Peas, Rice, etc.	Variable (60-80%)	Variable (slower)	Complete (in good compounds), less leucine	For vegans/vegetarians, people with milk/soy allergies, a complete plant protein for support is an excellent alternative.	Vegan, lactose/soy-free, often hypoallergenic, additional nutrients (fiber)	Lower % protein/leucine, taste/texture, potentially lower bioavailability, price
Bovine protein (hydrolysate)	Beef	≥90%	Fast	Different profile (more glycine/proline, less BCAAs)	For dairy avoiders, the paleo diet	Lactose-free, high % protein, contains creatine	Less BCAA than whey, the price of a plant-based protein supplement, a specific taste.
Egg protein (albumin)	Egg White	80-85% pure protein in the product.	Average	Complete, high BCAA content	Universal, for people who avoid dairy products	High biological value, complete, lactose-free	Price, potential allergen (eggs), taste/texture

How do protein supplements support your strength training?

The benefits of using protein supplements in the context of strength training are well documented scientifically. They are based on the fundamental role of protein in the adaptation processes of muscles to exercise.

Basic mechanism: protein balance

Two processes are constantly taking place in our muscles: muscle protein synthesis (MPS – building) and muscle protein breakdown (MPB – breaking down). At rest, on an empty stomach, decay prevails over synthesis. After a protein-containing meal, synthesis increases and exceeds breakdown, leading to a positive protein balance, which is crucial for protein for larger muscles. Strength training, although it is a catabolic stimulus in itself (it increases MPB), at the same time significantly sensitizes the muscles to the action of amino acids and enhances the MPS response to the ingested protein. The athlete’s goal is to maximize periods of positive protein balance, which leads to an increase in muscle mass (hypertrophy). Getting enough protein, including through supplements, is crucial to tipping this balance in favor of synthesis.

Stimulation of muscle protein synthesis (MPS)

Muscle protein synthesis (MPS) is the process by which the body uses amino acids to build new proteins in the muscles, which is the foundation for muscle recovery, repair, and growth after a workout. As mentioned, resistance training increases the sensitivity of the muscles to amino acids. Protein supplements provide a concentrated dose of amino acids, especially essential amino acids (EAAs), including branched-chain amino acids (BCAAs: leucine, isoleucine, valine). Leucine is recognized as a key “signaling” amino acid that initiates a cascade of processes leading to increased MPS. Numerous studies confirm that the consumption of protein supplements, especially those rich in leucine such as whey, significantly increases the rate of MPS in the post-workout period. Interestingly, research on combined training (strength + endurance) indicates that protein supplementation increases the synthesis of myofibrillar proteins (responsible for contraction), but not necessarily mitochondrial proteins (related to energy production).

Accelerated Recovery and Less Muscle Damage

Intense strength training inevitably leads to micro-damage to muscle fibers. This is a natural part of the adaptation process, but excessive damage and slow recovery can stunt progress. Protein provides essential amino acids to repair this damage. There is scientific evidence suggesting that protein supplementation may contribute to faster regeneration. Systematic reviews and meta-analyses indicate that peri-workout protein intake can help maintain muscle strength after a hard workout and reduce levels of markers of muscle damage, such as creatine kinase (CK). However, results on the effects of protein on delayed onset mysoreness (DOMS) are less consistent – some studies show no significant effect , while others suggest some benefits, especially with regular use. The combination of protein and carbohydrates can further support the regeneration process, m.in. by replenishing muscle glycogen faster.

Support for Building Muscle Mass (Hypertrophy) and Strength

The ultimate goal of many strength builders is to increase muscle mass and strength. Consistent maintenance of a positive protein balance, achieved through a combination of the right training stimulus and a sufficient supply of protein (including supplements), is the foundation of muscle hypertrophy.

Extensive systematic reviews and meta-analyses of scientific studies clearly confirm that protein supplementation, combined with regular resistance training, leads to a statistically significant increase in lean body mass (FFM) and muscle strength gains compared to training alone or training with placebo. This effect, although measurable, is usually moderate – meta-analyses indicate an additional increase in FFM of 0.3-0.5 kg over several weeks of training.

However, it is worth noting that the effectiveness of protein supplementation may depend on several factors. It seems that people who are already trained benefit more than beginners. The effect may also be smaller in older people. The initial supply of protein in the diet is also crucial – if someone already consumes the optimal amount of protein (e.g. 1.6 g/kg of body weight or more), additional supplementation may not bring further benefits in terms of muscle mass.

The benefits of protein supplementation are not the result of some magical action, but the optimization of the body’s natural response to training. Supplements amplify the anabolic signals triggered by exercise, ensuring that the essential building blocks – amino acids – are easily available. Strength training is a fundamental stimulus for adaptation , increasing the sensitivity of muscles to amino acids, which is especially important in the context of whey protein. Protein intake provides these amino acids. Supplements guarantee a timely and sufficient supply of these amino acids, especially key ones such as leucine, among athletes. , maximizing the MPS response induced by exercise. So they act as a catalyst, improving the natural adaptation process, rather than creating muscles out of nothing.

Although measuring an acute MPS response is often used as an indicator of anabolic potential, the relationship between short-term increases in MPS and long-term gains in mass and strength is complex. This is influenced by the total daily supply of protein and training consistency. The real benefits come from the cumulative effects over time. Studies on the acute response of MPS clearly show the benefits of protein. However, long-term studies highlight that total daily protein intake (up to about 1.6 g/kg) is a key determinant of weight and strength gains, and the effects of supplementation above this threshold appear to stabilise. The phenomenon of “full muscle” suggests that the MPS response to a single meal is time-limited. This means that while post-workout protein matters, a steady, adequate protein intake spread throughout the day, combined with progressive training, drives long-term results. Focusing only on immediate post-workout supplementation, without taking care of the overall diet and training, is an insufficient approach.

Optimal Use of Protein Supplements: When and How Much?

To take full advantage of the potential of protein supplements, it is worth knowing not only what to choose, but also when and how much to consume. While individual needs may vary, research provides practical guidance.

Timing matters? The myth of the anabolic window

The traditional concept of the “anabolic window” assumed a short period (usually 30-120 minutes) after training, during which the body is particularly receptive to absorbing nutrients, and protein intake during this time is crucial for maximizing muscle growth and recovery.

However, more recent scientific research suggests that this “window” is much wider than previously thought, and can last as long as 24-48 hours after a workout. This means that immediate protein intake after exercise is not absolutely necessary, especially if you have eaten a protein-rich meal before training and your total daily protein needs are met.

The most important factors influencing muscle adaptation seem to be:

Total daily protein intake: Ensuring the right amount of protein throughout the day (the aforementioned 1.6-2.2 g/kg of body weight) is absolutely crucial.
Protein Intake Distribution: Evenly distributing protein over 3-4 meals throughout the day seems to be more beneficial for MPS stimulation than consuming most protein in one or two meals.

In practice, consuming a portion of protein (e.g. in the form of a shake) within 1-2 hours after training is a convenient and effective way to provide amino acids during periods of increased muscle sensitivity and contributes to the achievement of the daily protein intake goal. However, there is no need to stress if you can’t do it exactly within 30 minutes. Protein intake before a workout can also be an effective strategy.

Shifting the focus from a narrow anabolic window to a holistic view of nutrition gives you more flexibility and reduces the pressure of having to eat immediately after a workout. Studies show that MPS remains elevated for a long time after exercise. Comparisons of immediate and delayed protein intake often show no significant differences in long-term gains if the total daily protein supply, including plant-based protein powder, is the same. Optimal MPS stimulation appears to be the result of a repetitive supply of adequate amounts of protein and leucine in meals spread throughout the day. This suggests that the body’s anabolic potential is not limited to a short post-workout period, but depends on your overall nutritional status and regular eating patterns. Therefore, the focus should be on achieving your daily protein intake goals with a sensible distribution of protein, which reduces the stress of the “window”.

How much protein do you need? Dosage Tailored to Your Target

As already mentioned, the general recommendation for strength training people is 1.6-2.2 g of protein per kilogram of body weight per day. During periods of particularly intense training or mass building, the requirement may increase to 2.5 g/kg of body weight.

When it comes to a single serving of protein (in a meal or supplement), research suggests that a dose of 20-40 g of high-quality protein is optimal for maximizing MPS stimulation in most people. Consuming larger amounts in one meal (over 40g) will not necessarily bring additional benefits in the context of MPS stimulation – excess amino acids can be used for other purposes, e.g. energy, or simply excreted.

An important concept is the so-called protein in the form of a supplement based on whey protein. “leucine threshold”. It is believed that a certain minimum amount of leucine in a meal, estimated to be about 2-4 g, is needed to effectively initiate MPS. This amount of leucine is typically found in 20-30 g of high-quality protein, such as whey.

It is recommended to evenly distribute your total daily protein intake over 3-4 (or more, depending on your preference and ability) meals or snacks throughout the day, at intervals of 3-4 hours. Such a scheme allows you to maintain a constant supply of amino acids to the muscles and repeatedly stimulate MPS throughout the day.

Example: A man weighing 80 kg, strength training to build muscle mass.

Goal of daily protein intake: 80 kg * 2.0 g/kg = 160 g of protein.
Spread over 4 meals: 160 g / 4 = 40 g of protein per meal.
Each of the four meals should provide about 40 g of protein. It can be a solid meal or, for example, a protein shake as a supplement.

The optimal protein intake per meal (20-40g) and the leucine threshold concept indicate that protein quality (amino acid profile) is as important as the amount of protein per serving to maximize anabolic response. MPS stimulation is dose-dependent, but only up to a certain level. Leucine acts as a key initiating signal. Different protein sources have different leucine content. Therefore, achieving an optimal dose of 20-40g with a leucine-rich protein (like whey) may be more effective at stimulating MPS than the same amount of lower-leucine protein (which may require consuming a larger portion of the latter protein ). This highlights the need to include both the amount and source of protein, such as whey protein isolate, in every meal or serving of the supplement.

How to Choose the Best Protein Supplement for You?

Choosing the right protein supplement is an individual process. There is no one perfect product for everyone. The following steps will help you make an informed decision:

Step 1: Define your goal Think about why you want to use a protein supplement. Is your main goal to build muscle mass with the help of protein preparations?

Building muscle mass with the help of vegetable protein for muscle support?
Accelerating regeneration after training?
Supporting fat reduction?
Supplementing protein deficiencies in the diet (e.g. vegan)?
Convenience and speed of meal preparation? The answer to this question will help narrow down the type of protein you choose (e.g. fast-absorbing whey after training, slow-absorbing casein before bed).

Step 2: Identify Limitations Consider your individual needs and limitations:

Intolerances and Allergies:
- Lactose intolerance: Avoid whey concentrate (WPC). Choose isolate (WPI), hydrolysate (WPH), vegetable proteins (soy, pea, rice, hemp), beef or egg. There are also special lactose-free versions of WPC available on the market.
- Cow’s milk protein allergy: Avoid all whey proteins and casein. Safe options are plant-based, soy, beef, and egg proteins.
- Soy allergy: Avoid soy protein.
- Celiac disease/Gluten intolerance: Most protein powders are gluten-free, but always check the label or look for certification.
Dietary preferences:
- Veganism/Vegetarianism: It is worth considering wholesome vegetable protein to support your diet. Choose plant-based proteins – soy, pea, rice, hemp, pumpkin seed, sunflower seeds or a mixture of these proteins.

Step 3: Analyze Composition and Quality Read the product label carefully, paying attention to:

Protein content: Check how many grams of protein are in a serving (usually 30g of powder) and what is the percentage of protein in 100g of the product. A good quality concentrate (WPC) should contain 70-80% protein, and isolate (WPI) or hydrolysate (WPH) above 90%.
Protein Source: Make sure what type of protein dominates the product (WPC, WPI, casein, soy isolate, etc.) and whether it is in line with your needs and limitations.
Amino acid profile: Ideally, the label should include information about the content of individual amino acids, especially BCAAs and leucine. A full amino acid profile indicates high quality. Beware of the so-called “amino spiking” – the unfair practice of adding cheap, incomplete amino acids (e.g. glycine, taurine) in order to artificially increase the result of measuring protein content using the Kjeldahl method (measuring nitrogen). Look for products with a clearly defined protein source and a full aminogram.
Extras: The shorter and simpler the list of ingredients, the better it often is. Avoid products with a lot of unnecessary fillers, artificial colors, preservatives or excess sugar. Sweeteners (e.g., sucralose, stevia) are common and generally considered safe in the permitted amounts, but some people prefer to avoid them. Thickeners such as guar or xanthan gum are often used to improve consistency and are considered harmless.
Sugar and Fat Content: Check the amount of carbohydrates (including sugars) and fats in a serving, especially if you are on a low-carb, ketogenic or reduction diet. Isolates and hydrolysates usually contain trace amounts of them.

Step 4: Consider Branding and Certifications

The reputation of the Protein Powder Manufacturer is important for consumers looking for quality. Choose products from reputable companies that have an established position in the market and have good reputations in terms of quality and production control. Read reviews, but be critical of them.
Quality Certificates: Look for information about independent tests and certifications. Certifications such as Informed Sport, Informed Choice or NSF Certified for Sport guarantee that the product has been tested for the presence of substances prohibited in sports and contaminants, and its composition is consistent with the declaration on the label, including pure protein. This is especially important for competitive athletes, but it also gives more confidence in the quality of the product to each consumer.

Step 5: Budget vs. Quality The prices of protein supplements can vary greatly:

The most economical option is usually whey protein concentrate (WPC).
Isolates (WPI) are more expensive than WPC.
Hydrolysates (WPH), beef proteins and some specialty plant mixtures are among the most expensive.

Think about what features are your priority and whether you are willing to pay more for, for example, higher protein content, lactose-free or a quality certificate. If you are lactose intolerant and are looking for a good product at a reasonable price, WPC can be an excellent choice. However, if the purity of the composition, quick absorption or you need to avoid lactose are crucial for you, investing in WPI may be justified.

The choice of a protein supplement is a multifactorial decision, in which individual needs (tolerance, goals, type of diet) intersect with the characteristics of the product (type, purity, additives) and external factors (budget, trust in the brand). There is no universally “best” protein for everyone. Individual physiological differences (e.g., lactose tolerance), dietary choices (e.g., veganism ), and training goals (mass vs. reduction ) are significant. Protein products vary greatly in terms of source, processing, purity, and added ingredients. Budget constraints are a practical reality , and trust and quality assurance matter. Therefore, the selection process requires a personalized assessment that matches these various factors, making it impossible to identify a one-size-fits-all product.

The presence (or absence) of certificates from independent organizations is an important, though often overlooked, quality indicator, especially in the context of compliance of the composition with the label and safety in terms of contamination. The supplement industry is not always subject to strict regulations regarding label claims and purity. “Amino spiking” is a known problem where manufacturers overestimate protein readings. Contamination with prohibited substances is a risk, especially for athletes. Third-party certifications (e.g., Informed Sport, NSF) mean that a product has undergone independent testing to verify its protein content, check for contaminants, and ensure safety. Therefore, prioritizing certified products when possible gives a greater degree of assurance about the quality and safety of the product, going beyond mere marketing claims.

Protein Safety: Side Effects and Common Myths

Protein supplements are generally considered safe for healthy people when used as directed. However, like any food product, they can cause some side effects, and many myths have arisen around their use.

Possible side effects and how to prevent them

The most commonly reported side effects affect the digestive system and include:

Bloating, gas, abdominal pain, diarrhea, nausea: These are the most common ailments. They are often associated with the presence of lactose in whey protein concentrates (WPC) in people with lactose intolerance. They can also result from eating too large a portion at once or drinking a shake too quickly.
- Solution: Choose a lactose-free supplement (WPI, WPH, plant-based, soy, beef, egg), start with smaller portions to assess tolerance, drink the shake slowly and make sure you consume enough fluids throughout the day.
Acne: There are anecdotal reports and limited research suggesting a possible link between whey protein intake and acne severity in some people. The mechanism is not fully understood, but it may be associated with effects on insulin and insulin-like growth factor 1 (IGF-1), which may be supported by a protein for athletes. However, this is not a rule and many people use whey protein without any skin problems.
Dehydration: A high-protein diet increases the production of urea, which must be excreted by the kidneys. This requires more water. Insufficient fluid intake with a high protein supply can lead to dehydration.
- Solution: Drink enough water throughout the day, especially on workout days and when using protein supplementation.
Effects on the Gut Microbiota: Research on the effects of protein supplementation on gut bacteria is still limited and yields inconclusive results, suggesting both potential benefits and possible negative effects depending on individual conditions and protein type.

Does Protein Harm Kidneys, Liver, or Bones? Debunking myths

Many myths have arisen around protein supplementation regarding its alleged harmfulness to health. It is worth confronting them with scientific evidence:

Myth: Protein damages the kidneys.
- Fact: In healthy individuals, even high protein intake (within the limits recommended for athletes) does not cause kidney damage. It increases the workload of the kidneys (they have to filter more metabolic products, such as urea), but healthy kidneys are adapted to this. The problem may arise in people with pre-existing kidney disease – in this case, you should consult your doctor before increasing your protein intake.
Myth: Protein damages the liver.
- Fact: There is no solid evidence that protein harms a healthy liver. The liver plays a key role in amino acid metabolism, but it is adapted to it. Concerns may relate to the situation of consuming excessive amounts of protein without adequate physical exercise, but this is not confirmed by studies on healthy, active people. As with the kidneys, caution is recommended in people with previously diagnosed liver disease.
Myth: Protein weakens bones and causes osteoporosis.
- Fact: This is one of the most widespread myths that has been debunked by numerous studies. Although a high protein intake may slightly increase the excretion of calcium in the urine, it also increases its absorption from the gastrointestinal tract. What’s more, protein is an essential building block of bone (it makes up a significant part of the bone matrix). Research suggests that an adequate supply of protein, with enough calcium, can actually support bone health, increase bone mineral density, and reduce the risk of fractures.
Myth: Protein “acidifies” the body.
- Fact: The human body has very effective buffering mechanisms (in the lungs, kidneys, blood) that maintain the pH of the blood in a very narrow, slightly alkaline range (7.35-7.45). Diet, including protein intake, has minimal effect on blood pH in healthy individuals. Although protein metabolism generates some acids, the body can easily handle them. The theory of “acidification” of the body by diet is largely pseudoscientific.

Soy protein and hormones: What does the research say?

Soy protein is sometimes controversial due to its isoflavone (phytoestrogen) content. Here are the facts based on the research:

Effects on Men (Testosterone, Estrogens): Concerns that soy lowers testosterone levels, raises estrogen levels, or causes gynecomastia in men are largely unfounded. Numerous meta-analyses of human studies have shown that the consumption of soy and isoflavones in amounts typical for a diet does not have a significant effect on the levels of sex hormones (testosterone, estradiol, estrone) in men. Extremely high doses could theoretically have an effect, but this is not the case with normal consumption of soy or soy supplements.
Effects on the Thyroid Gland Soy isoflavones may interfere with the absorption of levothyroxine, a synthetic thyroid hormone used to treat hypothyroidism. Therefore, people taking this medication should consume soy products at least 4 hours after taking the medication. There is no convincing evidence that soy harms thyroid function in healthy individuals with adequate iodine intake.
Potential benefits of phytoestrogens: It is worth remembering that phytoestrogens may also have beneficial health effects of whey protein, e.g. alleviate menopausal symptoms in women or potentially reduce the risk of certain cancers (e.g. prostate, breast).

Contraindications

The main contraindications to the use of protein supplements are:

Allergy to a protein source (e.g. allergy to cow’s milk proteins, soy, eggs).
Severe, previously diagnosed kidney or liver disease. In such cases, any significant change in diet, including increasing protein intake, should be consulted with a doctor.

Many of the perceived “risks” associated with protein supplements stem from myths, misinterpretations of physiological processes (such as renal filtration or pH balance), or extrapolation of animal studies or observations in specific disease states (such as existing kidney disease). For healthy, active people using supplements as directed, the risk is minimal and is mainly limited to potential digestive issues. Robust data from meta-analyses refute claims of bone harm or significant hormonal disruption in men caused by soy. Concerns about the kidneys often confuse the increased workload with the detriment of healthy organs. The body’s buffering systems effectively regulate the pH of the blood. Most of the reported side effects are mild and affect the digestive system. Therefore, evidence-based evaluation separates myths from reality, indicating overall safety for the target population when following guidelines.

The context of protein consumption in the form of a nutrient is important for potential side effects. Problems such as digestive disorders are often related to the dose or specific type of protein (lactose in WPC), while concerns about liver strain may only arise if high protein intake is not offset by metabolic demands resulting from exercise. Digestive problems are often associated with lactose or consuming a large dose at once. Suggestions for liver problems arise in the context of consuming protein without exercise. Adequate hydration reduces the burden on the kidneys. This means that side effects are not inherent in the protein itself, but are often due to the way it is consumed (type, quantity, time relative to activity, hydration). Optimizing your intake strategy (choosing the right type, managing your dose, taking care of hydration) minimizes the risk.

Diet First: Protein from Food vs. Food Supplements

While protein supplements can be a valuable tool in an athlete’s arsenal, they should never replace a balanced and varied diet based on natural foods.

The role of a balanced diet

The basis for healthy eating and achieving sports goals is a diet that provides all the necessary macro- and micronutrients. Natural protein sources such as meat, fish, eggs, dairy, legumes, nuts, and seeds provide not only proteins, but also vitamins, minerals, fiber, healthy fats, and other bioactive compounds that support overall health and body function. Supplements are by definition a supplement to the diet, not its foundation.

Protein Sources Comparison: Natural vs. Natural Supplements

Feature	Protein from Food	Protein supplements
Quality/Bioavailability	Usually high in animal products (complete protein). Variable in plant plants (often sources need to be combined). Plant digestibility may be lower.	Usually high (especially whey, casein, egg, soy). Isolates/hydrolysates have a very high bioavailability.
Convenience and Speed	It requires preparation, cooking, biting. Slower digestion (except for e.g. liquid dairy products).	Very high convenience, quick preparation (mixing with liquid). Fast absorption (especially WPI/WPH).
The cost of protein supplements in the store.	Variable, depends on the product (e.g. chicken vs. beef, lentils vs. nuts).	Variable, depends on the type and brand. Sometimes more profitable per gram of protein, sometimes more expensive.
Additional ingredients	A wealth of vitamins, minerals, fiber, fats, antioxidants, etc.	Mainly protein. They may contain added vitamins/minerals, but also sweeteners, flavors, thickeners.
Advantages	Full of nutrients, naturalness, satiety (fiber, fats).	Convenience, speed, precise dosing, targeted action (e.g. fast recovery), allergy free options.
Disadvantages	It takes time to prepare, and it’s harder to precisely control macros, especially in the context of protein for athletes.	Less nutritional value apart from protein, potential additives, cost, risk of “replacing” food.

When is protein supplementation most justified?

Bearing in mind that diet is a priority, protein supplementation is justified in specific situations:

High demand: When it is difficult to consume the required amount of protein (e.g. >150-200g per day) only from food, due to lack of time, appetite or the need to eat too much food.
Convenience: For people with a very busy schedule, traveling, or needing a quick post-workout meal/snack.
Specific time goals: When it is desirable to deliver amino acids to the muscles very quickly, e.g. immediately after an intense workout (although, as mentioned, this is not absolutely critical).
Dietary restrictions: For vegans and vegetarians as a reliable source of wholesome protein. For people with lactose intolerance or allergy to milk proteins as an alternative to dairy.
Calorie reduction periods: To help maintain muscle mass while being in a caloric deficit, where protein plays a key role in protecting muscle tissue and increasing satiety.

The optimal approach is not to choose “food OR supplements”, but to choose “food AND supplements”. Supplements should strategically fill in the gaps or offer specific benefits (like speed or convenience) that natural foods can’t always provide in a given context, all built on a solid foundation of a balanced diet. Natural foods are nutritionally diverse and form the basis of a healthy diet. Supplements offer specific advantages, such as convenience and fast absorption. None of these sources is universally better in all aspects. The most effective strategies leverage the strengths of both – using natural foods as their main source of protein, and supplements, such as whey protein concentrate, to meet specific needs or overcome logistical challenges. Seeing them as complementary rather than competitive tools leads to a more sustainable and effective nutritional strategy.

Summary: Key Protein Powders Information

Protein supplements can be a valuable part of the diet of physically active people, especially those who do strength training. Their main benefits include support in building and maintaining muscle mass, accelerating post-workout recovery, and helping to meet increased protein needs.

There are many types of supplements available on the market, differing in source (whey, casein, soy, plants, beef, eggs), degree of processing (concentrates, isolates, hydrolysates), absorption rate and amino acid profile. The choice of the right product should be dictated by individual training goalsand dietary preferences, body tolerance (e.g. to lactose) and budget.

Although the importance of protein intake in a narrow “anabolic window” after training has traditionally been emphasized, current scientific evidence indicates that it is more important to ensure an adequate total daily supply of protein (usually 1.6-2.2 g/kg of body weight for strength trainers) and evenly distribute it over several meals throughout the day (optimally 20-40 g per serving).

When choosing a supplement, it is crucial to read labels carefully, pay attention to the content and source of protein, amino acid profile and the presence of undesirable additives. The manufacturer’s reputation and possible quality certificates can be an additional guarantee of the safety and effectiveness of the product.

Many myths have arisen around the use of protein, especially regarding its alleged harm to the kidneys, liver and bones. In healthy people, with the recommended doses and proper hydration, protein supplementation is safe. The main potential side effects are mild digestive discomfort, often associated with lactose intolerance.

However, it should be remembered that protein supplements are only a dietary supplement . The basis should always be a balanced, varied diet based on natural foods, providing a full spectrum of nutrients. Supplements can effectively supplement the diet in situations of increased demand, time constraints or specific needs, but they cannot replace the value of whole food.

With this knowledge, you can make informed and rational decisions about including protein supplements in your nutrition and training plan, maximizing the benefits and minimizing the potential risks.

Protein Supplements: The Best Protein for Athletes