Glutamine and BCAAs in intact whey protein are peptide-bonded amino acids, meaning that they are part of the amino acid chains that make up the protein. On ingestion, these need to be broken down by digestive enzymes to release the amino acids that will then be absorbed into the blood stream. Peptide-bonded amino acids therefore take more time before they can appear in the bloodstream. Of course proteins differ in the speed at which they are digested and amino acids are released.

Primary protein structure is sequence of amino acids

On the other hand, Glutamine and BCAA supplements are free form amino acids. The body does not need to break down any protein to then obtain these amino acids. They are rapidly available to be absorbed into the bloodstream.


Assuming that you have now ensured adequate protein through a combination of food and protein supplements, there may be added benefits of using BCAAs and Glutamine as follows:

BCAA supplementation during cutting:

BCAAs are critical during cutting phases because you’ll be eating less carbohydrates and thus have low muscle glycogen levels, the prefered energy source for bodybuilding workouts. Training on low muscle glycogen leads to breakdown of muscle protein in order to obtain amino acids for energy. The BCAAs are the amino acids that are used up the most, in particular Leucine. In this case, supplementation with free form BCAAs is warranted as a means of minimising protein breakdown and muscle tissue loss. Furthermore, during a cutting phase protein intake is increased in order to make up for decrements in carbohydrate intake and as a means of sparing muscle protein for use as energy.

BCAA supplementation during mass training:

during a mass gaining phase energy provision is generally adequate, muscle glycogen is filled to capacity to fuel workouts and the risk of using muscle protein as fuel is lower. You can get away with not using a BCAA supplement in the presence of adequate protein intake and supplementation with whole proteins like whey protein which provide BCAAs already. However, there is increasing data from research showing that the BCAAs, particularly Leucine, can trigger anabolic signals inside your muscle cells and thus switching on muscle protein synthesis (see Fig below).

Leucine activates the important anabolic switch “mTOR”, providing a basis of Leucine supplementation in the free form

Such findings warranted the development of supplement protocols that included supplementing with free form BCAAs in between meals in order to keep the “anabolic switch on”. However, keep in mind that switching on anabolism is meaningful only in the presence of adequate supplies of all the other amino acids. There is a lot of interesting data on BCAAs which will be the topic of another article.

by Vic Veeraj Goyaram (africanmuscle)

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