The pancreatic secretion of intrinsic factor is reduced or absent, secondary dysbiosis of the intestine is common, and the mucosa may be compromised by the presence of excessive bacterial numbers and toxic metabolites
if you are using them, please discuss this with your GP
Abels, Improved distribution analysis of cobalamins and cobalamin analogues in human plasma in which the use of thiol-blocking agents is a prerequisite, Clinica Chimica Acta, Volume 131, Issue 3, 15 July 1983, Pages 211-224, ISSN 0009-8981 Thakkar, K., & Billa, G
BPC-157 & TB-500 Blend and Muscle
(PubMed) Nourhashemi F, Gillette-Guyonnet S, Andrieu S, et al
If deficiency is linked to diet, improving B12 intake may help maintain levels