Side effects from B12 supplementation are uncommon but may include: Mild gastrointestinal symptoms such as nausea or diarrhoea, typically with very high oral doses Headache or dizziness in some individuals Skin reactions (rash, itching) at injection sites when using intramuscular preparations Rare but serious allergic reactions, including anaphylaxis with injectable forms Hypokalaemia (low potassium) may occur during rapid correction of severe megaloblastic anaemia If you experience symptoms of a severe allergic reaction (difficulty breathing, severe rash, swelling of face or throat) after taking B12, seek immediate medical attention
Published research shows intact tripeptide absorption is typically 525%, with free amino acids (glutamate, cysteine, glycine) being reabsorbed and reconstituted intracellularly
Actionable Insight: Do a quick local search for "B12 injections near me." This will reveal a range of providers, from dedicated wellness centres to smaller, independent practitioners
10.1146/annurev-clinpsy-072120-014126[Epub ahead of print]
Neurourol Urodyn 2019
doi: 10.1126/science.1360704
