NICE CKS cks.nice.org.uk/anaemia-b12
2,3 Correction of deficiency different routes of administration Depending on the cause of the deficiency, different strategies to correct it can be applied, although in conventional medical practice the most common treatment is intramuscular (i.m.) injection of B12
Its unlikely Botox gets into breast milk in meaningful quantities
Other Uses Compounded methylcobalamin injections and other forms of vitamin B12 injections like hydroxocobalamin and cyanocobalamin may also be prescribed for those with pernicious anemia, diabetes, neuropathy, heart disease, circadian rhythm sleep disorders, memory loss, depression, fatigue, AIDS, inflammatory bowel disease (IBD), Lyme disease, osteoporosis, tendonitis, psychiatric disorders, Alzheimers disease, liver and kidney disease, and asthma

Self-administered B12 shots are generally recommended for individuals: whose bloodwork has documented low B12 levels Patients with pernicious anemia or a lack of intrinsic factor Individuals with Crohn's disease, celiac disease, or post-bariatric surgery malabsorption Vegans and strict vegetarians are unable to correct the deficiency through diet Older adults whose stomach acid production has declined with age Anyone on long-term metformin or proton pump inhibitors Across most of the U.S., injectable B12 is not sold over the counter a clinician has to write the script before a pharmacy can dispense it