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

In contrast, the recoveries of the conversion SIDA method were determined by analyzing a pork fillet sample spiked with CNCbl at three different levels (7.5, 37.6, 74.7 ng/g) while accounting for the endogenous B12 content of the sample in the recovery calculation
No clinically validated dose exists, as these are clinical practice patterns, not trial-tested protocols
This option is also used for migraine headaches, stress management and to promote overall wellness
The chart and calculator are for educational purposes only
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