A while back I noticed more and more of my friends taking ON Glutamine Powder.  I finally got curious enough and asked one of them about it.  Basically glutamine is the most abundant amino acid in our bodies.  As we wear down from working out, our bodies need to repair and this will help the process.  Forms of glutamine have been used to help people recover from surgery, so I think a post workout dose may do you some good.  Check it out at ON Glutamine Powder.