Lyophilized zfGH although stable at room temperature for 3 weeks, should be stored desiccated below -18 degree C. Upon reconstitution at > 0.1 mg/ml and filter sterilization zfGH mutant can be stored at 4 degree C for several weeks. At lower concentration addition of a carrier protein (0.1% HSA or BSA) is recomended. Please prevent freeze-thaw cycles.