Hmmmmm.....well I just found this:
"Any brand of growth hormone is stable at normal room temperature for up to two years without refrigeration. It should be kept cool as a precaution, for the same reason you like being in an air-conditioned room, or you keep an apple in the refrigerator. AFTER it is reconstituted, however, it is important to keep it in a refrigerator... but even then, the reason is not that the growth hormone is unstable. The reason is that when you stick in the needle of the syringe, you might be sticking in some bacteria, and you want to keep THEM cold so they don't multiply as much. Even though most bacteria are harmless, they can break down the growth hormone and make it lose potency, so you want to keep them cold and sleepy."
"Undiluted, freeze-dried HGH powder in sterile vials may be safely kept at room temperature, not to exceed 86 degrees Fahrenheit, for up to 18 months (as dated on each vial). Up to 110 degrees for a day or two before mixing may be tolerated without a problem. Once diluent is added, however, the resulting liquid HGH must be kept refrigerated and used within 4 weeks or potency will slowly decline."