b12 injection intramuscular or intravenous How to Give a Injection: Step-By-Step Instructions 10 Pack - B12 Intramuscular

According to SUCRA values, the top two ranked administration routes were the oral route (78.3) followed by the IM route (49.6) (Table 3(B))

B12 in dairy products is three times more bioavailable than B12 in meat, fish and poultry (1) However, the quantity of B12 is still lower in dairy than in most meats and fish

Simultaneously, they arent absorbing vitamin B12 well because of changes to their digestive tract

They both involve subcutaneous injections

"Comparative Bioavailability and Utilization of Particular Forms of B12 Supplements With Potential to Mitigate B12-related Genetic Polymorphisms", Integrative Medicine: A Clinician's Journal (Encinitas)