I work out. I take a whey protein supplement. The whey protein is made of amino acids bonded together. On the back of the can, it has a chart of the typical amino acid masses that are in the average serving. For example, it says that there is 450mg of Tryptophan per serving.
When Tryptophan is taken in its free-form, 450mgs would have very noticable mental effects because my body would convert it into serotonin. However, when I take the tryptophan, as a BCAA in the whey, there are no mental effects.
I realize that my body uses amino acids for other chemical synthesis besides protein. It seems though, that my body would prefer to use a free-form amino acid for these non-protein purposes.
Is this true? Does the body primarily use free-form amino acids for non-protein purposes. It certainly seems that way from my experience. There doesn't seem to be any good info on the net about this. I'm sure a biologist must know.