Whenever you have the option always use pharm GH. Even at a lower dosage, it's still much better than any generic. I switched from Serostim to Grey Tops just to see how good the greys are. And they are very good for a generic, but I noticed immediate water retention that I did not have with Serostim. So never again, Serostim or Humatrope from now on. Does anyone have an idea as to what is in the generics that cause this? I've heard many different things, but something is in them that causes the water retention and numbness they give. I've heard they're just a peptide blend, they contain ADH,etc.