B12 is naturally found in animal products such as meat, fish, eggs, and dairy
Morning on an empty stomach is the most common recommendation
Are you concerned about the health of your gums
References Huang Y, He Y, Makarcyzk MJ, Lin H
The standard NHS protocol for B12 deficiency typically involves hydroxocobalamin 1mg intramuscularly three times a week for two weeks (if there's no neurological involvement) or on alternate days until no further improvement (if neurological symptoms are present)
Mechanistically they do not overlap (GLP-1 agonists work through appetite and gastric emptying, this works on adipocyte lipogenesis and NAD+), and the mouse data specifically showed fat loss without reduced food intake, so they are not redundant