Some people do, using injections to correct low levels and oral supplements for maintenance in between
Vitamin B12, Fact Sheet for Health Professionals, National Institutes of Health, Office of Dietary Supplements Common questions about hydroxocobalamin, NHS (National Health Service), Hunt A, Harrington D, Robinson S
This method ensures rapid absorption, especially for individuals with absorption issues
Does the MIND diet improve cognitive function
Treat it as support, not a fat-burner
Animal proteins, including red meat, poultry, fish, eggs, milk and dairy products all have the vitamin