Benzyl alcohol does NOT act as a sterilizing agent in bac water. Bac water does NOT sterilize what you mix with it. It simply slows the growth of bacteria and fungi in what you mix it with. This is why many people recommend filtering the magic chinese peptides when you reconstitute, as an attempt to sterilize them.i'm not an expert so don't listen to me. but for what it's worth, my understanding is that the potential issue with bac water is that the benzyl alcohol part that is the actual sterilizing agent might evaporate over time through the puncture hole in the cap. and refrigerating it might actually accelerate this process. that's why bac is supposed to be stored at room temp.
i use my bac for far too long per guidelines but i'm not worried. seems like stuff evaporating through a tiny puncture hole is less risky than putting chinese powder in your belly.
The risk is not that the benzyl will evaporate, the risk is bacterial growth, which is increased with time after introduction.