What Is Tryptophan?

After the Thanksgiving feast has come and gone for another year, without fail, your relatives will probably comment on how sleepy they feel and blame it on the turkey. While a heavy case of the 'holiday-itis' is normal following the big meal, its cause is not necessarily cut and dry. What is tryptophan, anyway? Far from a mere scapegoat on which to blame the enjoyable excesses of festive feasting, this interesting chemical plays an important role in the human body that is worth knowing about.