Buy Durapex 100, made by SixPex, is the brand name for Nandrolone Phenylpropionate—most people just call it NPP. It’s an anabolic steroid, pretty fast-acting, and closely related to Deca-Durabolin (Nandrolone Decanoate). The main difference? NPP doesn’t stick around in your system as long. It kicks in quick, but it also clears out fast.You’re getting 100 mg of NPP per milliliter, in an oil-based injectable. SixPex manufactures it.