These may include: Nausea and stomach upset Diarrhea Constipation Injection site redness or swelling Itching Headache Dizziness Blood clots Swelling In rare cases, some people may experience an allergic reaction to vitamin B12, which can cause symptoms such as hives, difficulty breathing, and swelling of the face, lips, tongue, or throat
, ,
These properties include: Aqueous solubility (which affects dissolution) Stability in the acidic environment of the stomach and enzymatic environment of the intestine, Molecular size , and pKa (which determines its ionization state and ability to cross lipid membranes) 12 Dosage Form and Formulation: The design of the drug product can significantly impact bioavailability
Herrmann W, Obeid R
By sixty, that number drops to around 80 nanograms per milliliter
All three are prescription-only in the US and subcutaneous injections, and all require evaluation by a licensed provider