(Nandrolone Phenylpropionate). Durabolin is an anabolic steroid that was created by Organon in the late 1950âs and is officially known as Nandrolone Phenylpropionate. This anabolic steroid is almost identical to Organonâs Deca Durabolin (Nandrolone Decanoate), the only difference being the ester attached.Nandrolone Phenylpropionate). Durabolin is an anabolic steroid that was created by Organon in the late 1950âs and is officially known as Nandrolone Phenylpropionate. This anabolic steroid is almost identical to Organonâs Deca Durabolin (Nandrolone Decanoate), the only difference being the ester attached.