Total garbage. They’re twisting a scant few studies findings in very specific contexts (ie… restricted protein consumption, and complete fasting) in the face of a bounty of other evidence.)
It’s just marketing hoopla. And it’s dishonest, or embarassingly uninformed.
For endurance performance:
There is some limited evidence that BCAA ingestion alongside pre- or intra-workout beverages might enhance cognitive or motivational ability during endurance exercise. I have a list of supplements that I recommend for endurance sport. BCAA is on the very bottom of the list, but it does make the “maybe” list. But barely. There are half a dozen other things to take first, for endurance performance enhancement over BCAAs.
For health, and body composition:
Whey protein is derived from milk, and makes up ~20% of the protein found in milk. For the purpose of making whey protein powder, they just filter out the whey protein and either put it straight into a jug or do some additional filtering to make it finer and more easy to digest (this is where the names “concentrate, isolate, and hydrolysate” come from). In all types of whey protein, ALL of the amino acids are left in the protein in roughly their natural state. There are 20 of them. These 20 amino acids make up all the protein in your body. They serve as the building blocks for the proteins that are used to build muscle and perform most of your cellular functions. Three of these have been especially identified to be associated with muscle gain. They are leucine, valine, and isoleucine. Together, as a class, they are called the branched chain amino acids (BCAA) because their “side chain” (the thing that identifies each of the 20 amino acids) is branched.
In the absence of BCAA’s, muscle growth is limited, as compared to when they are present sufficiently in the diet pre-, intra-, and post-workout, and throughout the day. Whey protein has BCAA’s in it (more than most protein sources, actually), as does lean meat. Interestingly, whey protein and meat have enough BCAA’s in them such that the supplementation of BCAA’s doesn’t do anything additionally for hypertrophy or muscle retention during fat loss phases. Only during phases of incredibly tight caloric restriction, and in the slight absence of protein, are BCAA’s useful for preservation of muscle mass. If you’re eating whey protein before, during, or after your training session, and are eating at least .75 grams of protein per pound of body weight from lean meats/eggs/seafood ect, per day, there will be no measurable benefit to taking BCAA’s.