b12 injection insulin syringe Needle Size | B12 Syringes BD Ultra-Fine U-100 Insulin Syringe,

One very elegant design is to use a form of B12 that can be detected by rather sophisticated methodologies in a blood sample

[2] Pharmacokinetic studies demonstrate rapid systemic distribution with peak plasma levels occurring within 30-60 minutes of intramuscular injection, followed by extensive hepatic storage and enterohepatic recycling

Understanding potential sources of incidental exposure can help reduce confusion and improve communication during testing

But you cant just switch locations without adjusting your technique different spot, different needle, different approach

Pumpo R, Sarnelli G, Spinella A, Budillon G, Cuomo R (2001) The metabolism of nicotinamide in human liver cirrhosis: a study on N -methylnicotinamide and 2-pyridone-5-carboxamide production