Genotropin injectable human growth hormone made by Pfizer. Genotropin HGH is an FDA approved HGH injections that consists of a 191 amino acid chain. Genotropin comes in a 5.3 mg 16 IU pen that has separate compartments for HGH and bacteriostatice water. The HGH doesn't combine with the HGH until you twist the top of the pen to combine the HGH with the bacteriostatic water making the solution ready for injection.