does l carnitine work reddit Carnitine: the claims and why it may not Does L-Carnitine Really Work? An
Description
22b.2.1 Serum vitamin B12 Of the vitamin B12 in the serum, 2030% is attached to the transport protein transcobalamin (previously known as transcobalamin II), and the remaining 7080% is bound and carried by haptocorrin, the latter historically designated as transcobalamin I and transcobalamin III

They're not really a function of the dose being too high or your serum B12 level being too high

M.RamseyL

Wang P, Zheng M, Lau SY, Chen P, Mok BW, Liu S, et al
In high amounts, it's pro-oxidative
