These include injection site pain, headache, dizziness, and rarely, hypersensitivity reactions
While I have never used expired b12 vials since a pharmacist told me not to I have used multi-use vials after 28 days when they are supposed to be discarded and unrefrigerated once opened as well
Researchers use it in laboratory studies of fat metabolism under controlled conditions
Plasma riboflavin and vitamin B-6, but not homocysteine, folate, or vitamin B-12, are inversely associated with breast cancer risk in the European Prospective Investigation into Cancer and Nutrition-Varese cohort
References Cant C, Menzies KJ, Auwerx J
The LD control group was particularly distinct from the other groups in the unweighted UniFrac and BrayCurtis dissimilarity analyses plots, suggesting that animals exposed to the same diet at an early age in life diet develop similar microbiome profiles that persist even after an acute change in diet