Glutamine is an often recommended ingredient to be used in a post-workout drink. There are several reasons for this. First, many find that it reduces post-workout soreness. Second, research has found that glutamine can reduce the colds and flu's that many experience as a result of the immune system being depressed from intense exercise. Third, it reduces cortisol levels (this is huge!). Fourth, it increase growth hormone levels. And finally, many athletes find they recover quicker with glutamine use.