BCAA's are interesting.
Your money is better spent elsewhere if you're taking it for muscle building. I, too, threw them in the bushes once they (and Layne Norton's work) didn't show any difference in this department.
But they definitely alter brain chemistry. BCAAs compete with other "large neutral amino acids" for uptake in the brain, tryptophan and tyrosine being of note. A strategy of adding small amounts of tyrosine or phenylalanine to BCAAs (if taken on an empty stomach), or pairing BCAAs with meat ensures only tryptophan uptake is inhibited. This lowers serotonin synthesis and produces an overall dopaminergic effect.
Tried it daily for a month. Was never tired after morning exercise, hunger increased, and I was fukkin more often. Worked as expected.
The point: BCAAs have their legit uses.