Greibe E, et al. - Among populations with low and normal cobalamin (vitamin B12) status, the authors examined the absorption of synthetic cyanocobalamin and natural occurring hydroxocobalamin. In comparison with hydroxocobalamin, administration of cyanocobalamin resulted in a more than twofold increase in holotranscobalamin (holoTC). The absorptive capacity was reached only by doses above 3 μg cobalamin. When comparing uptake under different conditions, the outcomes highlighted the importance of using the same form of cobalamin.