Older adults are also more likely to take medications that can interfere with B12 absorption, Manson says
You should contact your GP if: You have been found to have elevated B12 levels on blood tests, particularly if levels exceed 1000 ng/L (approximately 740 pmol/L, though laboratory reference ranges vary) and you are not taking high-dose supplements You develop new symptoms after starting B12 supplementation, including persistent skin rashes, significant gastrointestinal disturbance, or unexplained symptoms You have underlying liver disease, kidney problems, or blood disorders and are considering B12 supplementation You are taking B12 supplements without medical supervision and have not had your levels checked, particularly if taking doses exceeding 2000 micrograms daily You experience symptoms that might indicate underlying disease, such as unexplained weight loss, persistent fatigue, jaundice, or abdominal swelling Call 999 or go to A&E if you develop severe allergic reactions following B12 injections, including difficulty breathing, facial swelling, or widespread rash, as these may indicate anaphylaxis, though this is extremely rare
Similarly, an earlier study published in the Journal of Nutrition found that children with a higher body mass index (BMI) had lower serum levels of vitamin B12 6
Tell your doctor if you are pregnant or breastfeeding
However, despite its promising mechanisms, AOD-9604 is not FDA-approved for medical use
Rather than being a peptide made from amino acids, it is a synthetic small molecule designed to inhibit the enzyme Nicotinamide N-methyltransferase (NNMT)
