I've used probably 5 or 6 different kinds of gh over the years, including of course Serostim. I'd say like MikeS says it wouldn't hurt, especially if you aren't going to use it all right away. However the Serostim does not come from the factory refrigerated, and generally hasn't been until it gets to you, so for Serostim it's not absolutely necessary to refrigerate it untl AFTER you reconstitute it, when of course you have to. Don't want to throw anybody off with this, so I'll repeat what BigA and MikeS said- it does depend on the brand and what they use in it - some (like Genotropin) DOES have to be keep under refrigeration at all times (including pre-reconstitution) or it will lose its potency for sure.