It does that because it helps with energy.? So some need to not take in the late afternoons.
Tyrosine, also called L Tyrosine, is not an essential amino acid since tyrosine can be made from the amino acid phenylalanine. Tyrosine is converted into dopamine and norepinephrine. Supplementation with both tyrosine and phenylalanine leads to alertness and mental arousal. Quoted from wwweb
I read today that it can bring along insomnia in not too high doses, so being pill people, more is not better. That's all that one needs to add to the existing WDs.
try goggling it...you might find that it is useful for many things.