B12 is water-soluble and any excess is excreted in urine there is no established upper tolerable intake level for B12 and toxicity from injection at standard doses has not been reported
Who might benefit from B12 supplementation
However, scientific research shows that very high-dose oral B12 (1,000-2,000 mcg) can be effective for some, as about 1% can be absorbed without intrinsic factor
Conclusion: Ensuring Optimal B12 Therapy Through Proper Dosing Getting the right dose of Vitamin B12 injections is key for good health
Headache Mild diarrhea Mild pain or redness at the injection site Nausea Serious or rare side effects Stop taking Vitamin B12 Injection and seek immediate medical attention right away if you experience any of the following: Allergic reactions, including angioedema, hives, and trouble breathing Signs of heart problems, including swelling, rapid weight gain, and shortness of breath Signs of hypokalemia, including muscle weakness, slow or irregular heartbeat Contraindications: This is not an exhaustive list of contraindications