Nothing, they are both the same. Igtropin is just a brand name. I cannot verify the quality of Igtropin though. Igtropin comes from china. If Igtropin has anything to do with Kigtropin, then i would stay away from it. And it likely does because they share the same logo. There are lots of peptide sources in the states that offer that peptide with purity certificates. I suggest you go with one of them. Ive been happy with Labpe, a sponsor right here at ology.