A: We have in stock: Eli Lilly Humatrope, Novo Nordisk Norditropin Flexpro pens, and Pfizer Genotropin. We only sell these four as they are the best brands in the world today, and have been around for lamost 30 years. They are all made bio-identical to what the body produces in the pituitary gland. All four are made from a 191 amino acid sequence which is also equal to what the body produces. The Eil Liily Humatrope has been the Gold Standard because it has been around since 1985, and the first HGH that was FDA approved to sell to the public. I would have to say that these top four brands are neck and neck as far as potency goes. There is many different types of HGH on the market today, so make sure you choose a top quality one for your HGH therapy.