A serum B12 test is a biochemical measurement of that amount, usually expressed in picograms per millilitre (pg/mL) or picomoles per litre (pmol/L)
Unreconstituted lyophilized peptides at -20C can remain stable for months to years
Duzel, A., Vlainic, J., Antunovic, M., Malekinusic, D., Vrdoljak, B., Samara, M., Gojkovic, S., Krezic, I., Vidovic, T., Bilic, Z., Knezevic, M., Sever, M., Lojo, N., Kokot, A., Kolovrat, M., Drmic, D., Vukojevic, J., Kralj, T., Kasnik, K.,
She also pursued additional study at the Roehampton University of London in the United Kingdom before participating in medical elective and mission work in China, the West Indies, and West Africa
While it might seem like a 1000 micrograms (mcg) B12 shot is equal to a 1,000 mcg B12 supplement, its not that simple