It is one of indispensable amino acid inside body, the content in a cup of milk is enough the effect that has to make the person sleeps peacefully, can make the person enters dreamland quickly.

• 它是体内不可缺少的氨基酸之一，一杯牛奶中的含量足够起到使人安眠的作用，可使人较快地进入梦乡。