How do you defend against this three-headed monster of muscle loss? Attack all three heads!
It's well established that branched-chain amino acids (particularly leucine) stimulate protein synthesis, and might do so to a greater extent than a normal protein on its own. BCAAs also increase synthesis of the cellular machinery responsible for carrying out the process of protein synthesis. Thus, BCAAs not only increase the rate of protein synthesis, but they also increase the cell's capacity for protein synthesis! Yep, you read that right.
BCAAs also work in your favor by reducing the rate of protein breakdown. They do this (primarily) by decreasing the activity of the components of the protein breakdown pathway, and also by decreasing the expression of several complexes involved in protein breakdown. (In this case, they decrease the amount of mRNA produced from the gene that codes for these components.)
If we revisit our original equation for muscle mass, it's plain to see that increasing synthesis and decreasing breakdown will equate to muscle gain/maintenance. And that, my friends, is how we fight the Cerberus of muscle loss.
Even More Beautiful
BCAAs have even more positive benefits than reduced breakdown and increased protein synthesis. They might also help improve workout intensity! BCAAs compete with the amino acid tryptophan for entry into the brain, where tryptophan can be converted to the neurotransmitter serotonin.
During exercise, serotonin levels rise and can (among other things) increase the perception of fatigue—that means a less intense workout for you.
BCAA supplementation reduces the amount of tryptophan that enters the brain, and therefore reduces the amount of serotonin produced. This might allow you to work harder, longer.
BCAAs And Whey
Despite the numerous positive benefits to BCAA supplementation, there are many skeptics who suggest that BCAAs are overpriced and that, to get more BCAAs, one should just consume more whey protein. While whey is rich in BCAAs, this isn't the most effective strategy.
BCAAs in supplement form are free-form, require no digestion, and are rapidly absorbed into the bloodstream.
The BCAAs in whey are peptide-bound to other amino acids and, in order to be effective, must be liberated through digestion and then absorbed into the bloodstream. Even though whey protein is relatively fast digesting, it still takes several hours for all the amino acids to be liberated and absorbed into the bloodstream.
BCAAs in supplement form, however, are free-form, require no digestion, and are rapidly absorbed into the bloodstream. They spike blood amino acid levels to a much greater and faster extent than peptide-bound aminos. Even a few grams of free-form BCAAs will spike BCAA plasma levels to a much greater extent than 30 grams of whey protein, thereby having a more immediate impact on protein synthesis and protein degradation.
Additionally, since BCAAs bypass the liver and gut and go directly into your blood stream, they can be used as an immediate energy source during your workouts. Valine and isoleucine are considered glucogenic amino acids, meaning they can be converted to glucose and serve as an important energy source during exercise to help fight off fatigue during your workouts.