what do b12 injections do for dogs Vitamin and Dogs: Is Your Dog Deficient? – AnimalBiome Vitamin B12 Injection For Dogs:

Slower absorption When high doses of B12 are injected, the body can only store so much before excess is excreted

[2] [16] Dietary deficiency without neurological features: Initial loading doses followed by maintenance therapy, with consideration of oral supplementation in appropriate cases

In his review in Blood, Ralph Green hematologist, Department of Pathology and Laboratory Medicine, University of California, Davis, recommends at least 10mcg/day of daily vitamin B12 to prevent problems

302 Blood levels of the AGEs pentosidine and carboxymethyllysine were found to be higher in 41 subjects with fibromyalgia than in healthy individuals