The well-known geriatrician-haematologist Larry Solomon, working at Yale University in the USA, wrote 20 years ago: if I had treated only those people who actually had too low serum B12 and elevated MMA values, then I would not have treated approximately two-thirds of the people with a favourable response to B12 supplementation (note: partly via injections, partly via oral supplementation)
Applications in Research As a molecular tool to study growth hormone fragmentspecific signalling mechanisms
You should experience less fatigue, enhanced energy levels, and fewer aches and pains
But if you dont have enough B12, those processes slow down and you feel tired and exhausted
Whilst the NHS notes that taking up to 2,000 micrograms daily is unlikely to cause harm in most people, there is generally no benefit to consuming such excessive amounts unless treating confirmed deficiency under medical supervision