Where did you get it? Was it already reconstituted? What was in reconstituted in? I'm in the middle of some research on this topic. Number one, most IGF that is already reconstituted when you receive it, you have a 50/50 chance that its degraded to almost half or 1/4 of what its normal strength is anyway. Number two, if its lypholisized powder wafer, and you reconstitute it, one day may not hurt too much, may degrade some, but put it back in the fridge. The variation of temperature will probably cause the degradation, but its probably still good. I will not buy already reconstituted IGF anymore.........if you think about it, its common sense, treat it like GH. You wouldn't buy already constituted GH, who knows whats growing in there and your probably injecting 10%IGF, 90%BW or acetic acid. Just my opinion.......