Increase in circulating holotranscobalamin after oral administration of cyanocobalamin or hydroxocobalamin in healthy adults with low and normal cobalamin status.
Greibe E, Mahalle N, Bhide V, Heegaard CW, Naik S, Nexo E.
Eur J Nutr. 2017. doi: https://doi.org/10.1007/s00394-017-1553-5

Effect of 8-week oral supplementation with 3-µg cyano-B12 or hydroxo-B12 in a vitamin B12-deficient population. 
Greibe E, Mahalle N, Bhide V, Fedosov S, Heegaard CW, Naik S, Nexo E.
Eur J Nutr. 2017. doi: https://doi.org/10.1007/s00394-017-1590-0