When oral doses exceed the capacity of the stomach's Intrinsic Factor receptors, the body absorbs the remaining B12 via a process called passive diffusion
that comes out to .58 cents a pair
[DOI] [PMC free article] [PubMed] [Google Scholar] Ladanyi A, Mukherjee A, Kenny HA, Johnson A, Mitra AK, Sundaresan S, Nieman KM, Pascual G, Benitah SA, Montag A, Yamada SD, Abumrad NA, Lengyel E, 2018
The mechanism is deceptively simple
In vivo studies have shown that intravenously administered NAC reaches high concentrations in organs such as the lungs (320 M), kidneys (250 M), heart (170 M), and liver (100 M), with peak concentrations in human red blood cells reaching 200 M
Time course of changes in variables of ROS production in PBMC is displayed in Supplementary Table 2