It is important to distinguish between medically indicated B12 injections prescribed for deficiency and lipotropic injections, which are typically unlicensed medicines in the UK and lack robust clinical evidence for weight loss
It has historically been criticized because digestive enzymes can break down glutathione before it reaches circulation intact
Too little and you are working with concentrations so high that tiny measurement errors become magnified into real dosing problems
It can also cause infertility in men and increase the risk of testicular cancer
9 , e017759 (2020)
17: Sikiric P, Boban Blagaic A, Krezic I, Zizek H, Kalogjera L, Smoday IM, Vukovic V, Oroz K, Chiddenton HM, Buric S, Antunovic M, Gojkovic S, Strbe S, Skocic M, Sikiric S, Milavic M, Beketic Oreskovic L, Kokot A, Koprivanac A, Dobric I, Sever M, Staresinic M, Batelja Vuletic L, Skrtic A, Seiwerth S