Why can (not) BCAA supplementation be better than EAAs?

Why are new essential amino acid supplements (EAA), almost displacing the previously very popular BCAA ? This is probably the hottest fitness debate in the last few years.

But I will emphasize the first thing at the beginning. BCAAs are an advanced supplement, the potential of which will be used only by a certain part of athletes! In my opinion, EAAs are a supplement that is important only for people who have a certain type of allergy. For another 99% of people, it is far more appropriate to consume as a source of all proteinogenic amino acids complete protein (e.g. whey protein isolate), or hydrolyzed peptides (even faster absorption than free amino acids).

EAA vs Proteinogenic Amino Acids

About 20 amino acids are needed to make muscle protein. These are considered to be so-called proteinogenic amino acids and include leucine, isoleucine, valine, lysine, methionine, phenylalanine, threonine, tryptophan, histidine, cysteine, tyrosine, arginine, glutamic acid, aspartic acid, serine, asparagine, glutamine, alanine, proline and glycine.

Of these twenty, the first nine are considered essential amino acids, abbreviated to EAA. Essential because our body cannot produce them, which means that we have to get them from food or food supplements (while non-essential amino acids can be synthesized from other amino acids).


9 essential amino acids (EAA):


  • Leucine *
  • Isoleucine *
  • Valine *
  • Lysine
  • Methionine
  • Phenylalanine
  • Threonine
  • Tryptophan
  • Histidine

* Branched chain amino acids (BCAA)

Of the nine EAAs, there are three so-called BCAAs: leucine, isoleucine and valine. However, this does not mean that they are the same as the other six EAAs. They have a difference in chemical structure and this makes them unique and at the same time, and we come to the essential, especially effective for stimulating the synthesis of muscle proteins!

What makes BCAAs special and how do they different from other EAAs?

All nine of the above amino acids are essential, but only leucine, isoleucine, and valine have a branched-chain chemical structure. What does that actually mean? Very simply: BCAAs are the only amino acids with a “branched” V-shaped structure at one end, while none of the other six EAAs have this specificity. Importantly, however, this specificity of the chemical structure is extremely important. The structure and shape of an amino acid largely determines how the body works with it. It is very important for us that the branched structure allows leucine, isoleucine and valine to completely bypass the liver and thus be very available.

And that’s important! Other EAAs must pass through the liver after ingestion. Once in the liver, the body decides whether to a) send amino acids to the muscles or b) convert these amino acids to glucose.

One of these two scenarios can occur with the remaining six EAAs, while with three BCAAs (leucine, isoleucine, valine), only one thing can happen, and that is to bypass the liver and reach the muscle cells expressly!


So EAAs that are not called leucine, isoleucine or valine do not provide the benefit of fast availability!

The key player, as we know, is leucine. Today, we know that leucine stimulates MPS (muscle protein synthesis) better than any other amino acid. So we want the leucine to reach the muscles and fire the MPS as soon as possible.

We have the basics behind us, and now I can explain why I think the use of BCAAs is justified, while a mixture of all nine EAAs is more or less meaningless.

As I suggest above, at a particular time, using six EAAs is at least useless (it may even be anti-productive, but that’s for the next article). And what is that particular time? Try to answer first when you take BCAAs, and therefore a mixture of all EAAs? I will answer for you. You take them in the period around training. Why would you use them another time, right? Probably not taking these supplements while you are hungry, right? 

The explanation is simple! The studies compare the use of only BCAA or only EAA, on an empty stomach without other nutrients! Which in practice almost never happens.

There is a huge problem with the “empty stomach” method: in practice, you never take one or the other supplement. Or is it? As we know, in the fitness methodology we use the timing of food intake as well as supplementation. Therefore, it can be assumed that you are not completely hungry at the time you take BCAAs or EAAs. Am I almost sure about that? And that’s important. Most studies are based on ensuring identical (read in practice unrealistic) conditions. Researchers must apply functional substances such as BCAAs or creatine to an empty stomach without any other nutrients; otherwise, it is difficult to prove what the real benefits, if any. Another limiting factor is that most scientists do not practice and therefore have no practical experience. Unfortunately, due to this, their study proposals are in many cases flawed from the beginning.

Amino acids are just the building blocks of protein, which means that every protein you eat breaks down into amino acids, including EAA. Therefore, we have another and much more relevant discussion about whether it is really necessary to use free amino acids. 

In any case, most of us receive enough of all the proteinogenic amino acids from our diet and protein supplements.

Now “new” studies in favour of the EAA. Key question: Why did EAA supplements in some studies provide better support for MPS than BCAA?

The answer is simple. If you are hungry. So really hungry! Which in practice is only in the morning after waking up. So at the moment, using EAA brings more benefits than BCAA! This is the only time that the use of EAA can be defended in some way.

Surprisingly, a much better way is to supplement the complete protein in the morning. And it is even possible to supplement it with the BCAA. Why? The purpose of BCAA use is to maximize muscle growth by enhancing MPS in the presence of all 20 proteinogenic amino acids. If you don’t have enough of all 20 amino acids, it won’t matter how much you take EAA or BCAA, because neither will increase MPS alone enough! However, in comparison, EAAs are more effective than BCAAs alone. However, this only applies to use on an empty stomach, and then it is true that the more essential amino acids, the better. 

However, when you compare BCAA supplementation versus EAA with complete proteins that provide all 20 proteinogenic amino acids, BCAAs are a better way thanks to their unique structure to ensure that they are immediately available. In fact, a study that used BCAAs with food confirmed that adding BCAAs to food led to higher levels of protein in the muscles. It should be noted that this was not a food that would be rich in BCAAs.

So let’s practice when to take BCAAs, if we evaluate that we need them.

Because neither BCAAs nor even EAAs provide all the amino acids needed to make muscle protein, you need to know when to use BCAAs (EAAs will no longer be considered) to provide a truly ergogenic (performance-enhancing) effect.

Basic tips for using BCAA:


  • Before exercise – give the muscles energy and delay fatigue.
  • After exercise – to increase muscle protein synthesis (MPS). A practical study confirmed that the addition of 3-5 g of free leucine to whey protein increased the increase in muscle mass in the long run.
  • With meals throughout the day – to increase the leucine content in meals for larger MPS.

Author: Pavel Samek

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