Well, hell, I go looking for the amino acid my brain can never remember, the one that is in both milk and turkey (I think) that starts with T (tyrosine? transcobalamin? thymine? tartar? no, no, I can't remember it, dagnabbit, and never can)
Anyway, in looking this amino acid up, yet again, since I can't ever remember it (it is sort of like Calodendron capensis, a tree I can never remember either, unless I don't need to) I ran across a bunch of links on melatonin in milk.
Here's one -
http://www.mckinley.uiuc.edu/health-info/dis-cond/misc/insomnia.html
The thing is, the whole ritual of putting a mug of milk into the microwave, or on the stove ... the ritual part is additive. One should put on bunny slippers and a comfy robe. Ok, males should put on a comfy robe and scuffed flipflops.
I am only half kidding.
AHA, I REMEMBERED, it's tryptophan that I was trying to conger up.
Whew.