best protein sources for muscle building

Best Protein Sources for Muscle Building – [Science-based]

Protein is important for muscle building. It provides sufficient amino acids to repair and create muscle. But not all proteins are the same. If you want to optimize your gains, you should aim for the best protein sources for muscle building. But what are they? And how can you identify them?

In this post we'll talk about amino acids, types of proteins, plant-based and animal-based and their biological value. Are you ready? Let's go!


Muscle building, also known as muscle hypertrophy, is determined by two main factors; resistance training and protein intake. The first induces a catabolic state and gives reason to our body to create more muscle; the second provides amino acids for protein synthesis and triggers anabolism (study)

By playing with both cards (resistance training and protein intake), what you want to achieve is a positive net protein balance. This is, that your muscle protein degradation (MPD) is lower than muscle protein synthesis (MPS) (study).

A wide variety of studies have investigated the role of protein in muscle building. During this study, protein affected muscle hypertrophy, performance, training session recovery, lean body mass, and strength (study). And this is just an example of all the evidence behind protein for muscle building.

Recommended Protein Intake

As you saw in this post (click HERE), recommendations of 2-3g/kg daily protein seem to be optimum for muscle building and recovery. However, this is far from the RDA (study), staying at a simply too low 0.8 g/kg. This is a mere preventive dose to avoid protein insufficiency, but we can definitely benefit of higher doses.

People seeking for muscle building (YOU) definitely need higher protein doses (study). This is because of the high energy demands, fasten metabolism and high degree of muscle damage. But, if you want to keep reading on this topic, we recommend you this post!

How much protein do i need to build muscle


Now you know how much protein you need, but are all protein sources the same? Not really. Protein sources differs on their amino acid profile, bioavailability, digestibility,... (study) Therefore, we can't say the protein of an egg and legumes is going to have the same effect on muscle building.

There are ways we can classify proteins to find the best protein source for muscle building. The main features to consider are:

  • Amino Acid Profile
  • Biological Value
  • Digestibility

Amino Acid Profile

Proteins are large macromolecules formed by amino acids joined together by peptide bonds and other molecular interactions (study). There are 20 Amino Acids (Aa) forming all proteins known. Out of this 20Aa, only 9 are essential, meaning that we cannot synthesize them on our own, and we need them from dietary sources (study). The remaining 11 Aa, we do synthesize them edogenously, and although it's important to get them from the diet as well, is not strictly essential.

Amino Acids

The idea of essential and non-essential Aa triggered a lot of research finding amino acids composition on different foods and the impact on protein synthesis (study). With this came the concept of Amino Acids Profile (study), which helped evaluating the quality and content of each amino acid.

Protein sources containing all essential Aa are known to be complete proteins. On the other side, those lacking one or more essential Aa are considered to be incomplete proteins. Here we generally find plant sources (study)

Protein Sources

In this figure you can see the %EAA (Essential Amino Acids) of different proteins sources. In white, plant sources. In grey, animal sources. And in black, human muscle used as a reference. Plant proteins sources tend to have lower content in EAAs when compared to dairy products or other animal proteins.

Comparing the amino acid profiles of all these sources, the researchers found plant proteins sources to be generally defficient on methionine (almost nothing) and cysteine (study). Also, leucine, which is the most important Aa for muscle protein synthesis (study) was considerably higher on animal protein sources.

Biological Value

There are different methods of classifying proteins sources to get a better overview of the quality of each source (study).

Biological value measures protein quality by calculating the nitrogen used for tissue formation divided by the nitrogen absorbed from food (study). This measurement gives an overview of how well is your body at using an specific protein source for metabolic work. The assesment can be used to compare between proteins to find the best protein sources for muscle building.

Biological Value

Research has been able to determine the biological value of a lot of different protein sources, both animal and vegetable. Taking the egg as reference with a result of 100, it's only overpassed by whey protein, with a result as high as 159, depending on the amino acid profile of the blend and the raw material.

Animal proteins sources are also at the top of the table, followed by the vegetable sources. Biological value takes into consideration the amino acid profile (study), and the lack of one or more essential amino acids makes vegetable sources rank lower on the table.

Other Properties

A lot of the protein assesments discussed only consider the ingestion of protein alone. However, in reality we seldom do that. It's almost always accompanied by a source of carbohydrates and/or fats.

The presence of other macronutrients on our meal affects the way protein is absorbed, digested and used. In this study (study), carbohydrates coingestion with protein delayed protein digestion. However, the postprandial (after ingestion) protein accretion didn't differ from the other group, and the anabolic response was the same after all.

Similarly, fats seem to act the same way when co-ingested with protein sources (study). Both cases affect delays digestibility, but the anabolic response doesn't differ, suggesting that the structure and composition of the protein is not modulated by the presence of other macronutrients.


Protein sources may differ on their amino acid profile, digestibility, biological value or the efficient ratio of amino acids being used for anabolism. Based on these differences, one can discuss different protein sources to be able to answer the question; what's the best protein source for muscle building?

Plant-based protein

The fact that whey and animal protein show higher properties as protein sources doesn't mean that we cannot use other protein sources to reach our protein intake.

The more complex nutritional matrix of these food sources show a slightly different protein's kinetics and digestion (study). And yes, it does produce a lower anabolic respone, but there are some strategies we can use to prevent that:

  1. Higher protein intake to provide sufficient amounts of all amino acids
  2. Mix protein sources to create a complete protein
  3. Intake of fortified foods with lacking Aa
Protein Sources for muscle building

In figure b), you can see how the plant protein blend, composed of different plant-based proteins, showed a greater anabolic response than 20g plant protein alone. The same happened with 40g plant protein (study).

Both options discussed lead to the same point; achieving a more favourable amino acid composition to repair and create muscle. At the end of the day is the amino acid pool  what determines the degree of anabolism in our muscle tissue.

Animal Protein

Animal Protein, either we like or not (sorry vegetarian people), has shown to be the most effective protein source for anabolic response (study)(study). This is due to its complete amino acid profile and the readily available protein content, making them rank higher on the table.

Animal protein also shows a high content in leucine. Leucine, on its hand, is the amino acid responsible of triggering and activating mTORC1, highly correlated with muscle protein synthesis (MPS) (study). However, leucine is not enough to carry out protein synthesis itself, and it needs of all other amino acids. This is where the complete amino acid profile of animal sources comes into play.

Whey Protein

Within animal sources, whey protein and derived products show the highest biological value, amino acid profile and leucine content. Therefore, whey protein products are the best protein source for muscle building.

Whey protein, besides its high content in leucine, it's also considerably high in cysteine. This amino acid has been shown to have strong antioxidant functions (study), providing additional health benefits. These include lower risk of cancer, fight of chronic oxidative stress and regulating the inmune system (study).

Casein, on its hand, also seems to be one of the best protein sources for muscle building. Its nutritional matrix is similar to that of whey protein, but with added calcium and phosphorus (study). Casein, however, tends to for a gel-like structure in the digestive tract, delaying and prolonging the anabolic reponse over time. This can come handful before going to bed or any other situation in where there won't be any protein intake for a long time (>6h)

Extra Benefits of Whey Protein as Protein Source for Muscle Building

Whey protein is probably one of the bests protein source for muscle building. And, to sum up what we said before, this is why:

  • Highest biological value
  • High content in leucine
  • Contains all essential Aa
  • Rapid digestion

In addition to the direct impact of whey protein in the anabolic response, there are some other mechanisms by which whey protein could potentiate muscle building.

Antioxidant effect

Whey protein acts as a potent antioxidant food. It has shown to replenish gluthatione (study), the most powerful antioxidant in our body (study). This could help modulating excess oxidative stress after exercise.

Due to this, whey protein can potentially minimize muscle damage and recovery (study)

Increased Anabolic Response

Whey Protein ingestion leads to a higher anabolic response when compared to other protein sources (study). It also increases ribosome biogenesis (study). More ribosomes increase the rate of translation and protein synthesis, producing more proteins per unit of time.

If you want to know more about whey protein, click HERE!


Now we get into the fun part. What's the ultimate best protein source for muscle building?

Let me disappoint you, but there's no "ultimate best protein source". All protein sources have their 'pros' and 'cons'. However, from TBS, we recommend you following a balanced nutrition, including different types of protein. 

While whey protein derived products show to be the best protein source for muscle building, there are some aspects in where other protein sources win by.

Natural protein sources, on their hand, contain protein within a nutritional matrix. This complete nutritional matrix acts in synergy, helping digesting and activating anabolic pathways related to muscle building (study).

It's a mistake to think only protein affects MPS. In fact, a balanced diet rich in micronutrients increases the rate of MPS (study)

Types of Protein Sources


Whey Protein may be the best protein source for muscle building alone, but the nutritional matrix of other protein sources improves protein kinetics, absorption and potentially leads to higher long-term adaptations. Don't base your diet in a sole protein source. Vary different sources and create a nice balance between them.


Muscle building requires of high protein intakes to create a positive net protein balance. But not all protein sources are the same. Aspects such as amino acid profile, biological value or protein kinetics affect the anabolic response. But what's the best protein source for muscle building?

In theory, whey protein shows to be the best protein source for muscle building. However, the nutritional matrix by which protein is contained in other protein sources may increase digestibility, kinetics and long-term anabolic response. For this reason, we advice you not to depend solely of whey protein, and create a balance diet with different protein sources.

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