Some people think that this amino acid makes you drowsy. I tend to agree, since every time I have a turkey sandwich for lunch, I just want to go to sleep about an hour later.

structural formula of tryptophan:

                         O        H
                          \\     /
     H        H   H   H    C -- O
      \      /     \ /    /
       C == C       C -- C -- N -- H
      /      \     /      \    \
H -- C        C - C        H    H
      \\     //   \\
       C -- C       C       tryptophan
      /       \   /  \      C11H11N2O2
     H          N     H
                |
                H