There was an interesting topic on one of the other CP forums about using amino acids as a CP fertiliser. The topic mainly concentrated on using it in Heliamphora pitchers. I've been trying this myself by applying a small amount of L-glutamine powder to the pitchers of my Heliamphora heterodoxa x ionasii and it it currently putting out six new pitchers, with the latest one to open being a good size. My trial is in no way scientific, as I am not performing a comparison between this and a non fertilised Heliamphora but the growth rate does seem to be good for a plant that doesn't receive any other nutrients.