Some do, especially if theyve been low on B12 for a while
If it was anything other than sterile saline, it may have been a preservative that you reacted to, such as benzyl alcohol
However, under reducing conditions, the cobalt center is reduced to Co(II) or even Co(I), which are usually denoted as B 12r and B 12s , for reduced and super reduced respectively
"Personally, the stuff that I take is from a compounding pharmacy, and you know they have third-party testing certification, and I can look up the batch number and find the certificate for all the testing, and so I kind of know that the purity level is 100%." "Even with the risks that have probably been told to you or the risks that you've read about, does the reward outweigh the risks?" Robertson asked