In this review published in Integrative Medicine: A Clinician’s Journal in 2017, forms of B12 supplements with potential to mitigate B12-related genetic polymorphisms were compared for their bioavailability and utilization. The study had three objectives: (1) To summarize and compare assimilation pathways for four B12 forms; (2) to determine whether supplementation with a particular B12 form (or combination of forms) presents any advantages for the general population or for individuals with single nucleotide polymorphisms (SNPs) in B12-related pathways; and (3) to address misconceptions regarding B12 forms, methylation pathways, and various SNPs reported in commercially available tests. Concluding that supplementing with any of the natural bioidentical forms of B12 (MeCbl, OHCbl, and/or AdCbl) is preferred instead of the use of CNCbl.
Paul C, Brady DM. Comparative Bioavailability and Utilization of Particular Forms of B12 Supplements With Potential to Mitigate B12-related Genetic Polymorphisms. Integr Med (Encinitas). 2017;16(1):42-49. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5312744/