Recently, there has been an increasing trend of consuming branched-chain amino acids (BCAAs) during training, and the reasons for this are multiple. Thus, for example, BCAAs are easily digested and quickly enter your muscles, thus preventing their breakdown. In addition to this, they are usually flavored and represent a more attractive and tasty way to hydrate compared to ordinary water.

BCAAs are made up of three essential amino acids (EAAs): leucine, isoleucine, and valine. Of these three, leucine has been shown to be the amino acid that has the greatest impact on muscle building and recovery. So BCAAs are more than an obvious choice if we want to build muscle, right? Maybe not really.

There is evidence to suggest that protein synthesis is driven by factors other than leucine-rich BCAAs vs EAAs, and that the choice of a complete protein (a protein containing all 9 essential amino acids) could be a better choice.

Understanding the role of leucine
In a study conducted on rats published in The FASEB Journal, the researchers observed increased levels of leucine in the blood after protein synthesis stopped and returned to normal. If muscle building stops while there is still leucine in the blood, then this indicates that maximal protein synthesis is affected by factors other than leucine.

Creating optimal protein synthesis is an energy-intensive process. And while leucine has been shown to optimize muscle building peak, it may not be the best at maintaining it. In other words, leucine is a great trigger for protein synthesis, but not for maintaining it, which can be especially a problem during longer workouts, after all, you want protein synthesis to last as long as possible.

Choose a better protein
Studies conducted on rats and humans have shown that muscle can make better use of “intact” leucine (the type of leucine found in protein powders) than leucine in free form (the one found in BCAAs). This research suggests that protein should provide greater protein synthesis than BCAAs.
In a similar study, the elderly received either essential amino acids (EAAs) or a protein that contained an identical amount of EAAs. At the end of the study, it was shown that people who received protein had a higher protein balance. But why?

Looking behind the leucine
Dr. Mike Roberts and his team from the Laboratory for Molecular and Applied Sciences at the University of Auburn conducted preliminary research on the role of other bioactive components in protein and their stimulation of protein synthesis. The researchers specifically investigated “protein exosomes.”

Exosomes are nanoparticles found in blood, saliva and other body fluids. Their role in the body is to carry protein and other compounds through the body. Using a sophisticated methodology. These nanoparticles have a particularly positive effect on protein synthesis.

When you consume protein, in the first 1-4 hours, increased protein synthesis will be the result of leucine, which is found in protein. However, you can also feel a moderate and continuous increase in protein synthesis even after 4 hours thanks to the exosomes found in the protein that will continue this process in the skeletal muscle.

Make a smart choice
To date, there are not enough definitive studies to confirm and say that a rapidly absorbing protein is superior to supplements containing only BCAAs. However, most research is leaning in that direction. If you want to maximize muscle growth or maintain your existing muscle mass, the choice of protein seems to be a smart choice.