red spot after b12 injection Possible allergic reaction to injections?? : r/B12_Deficiency B-12 Injections - Phoenix Rises

Too much signal and the doseresponse curve flattens - you spend more money and expose yourself to more side effects for no extra benefit

Blood levels peak around 1-2 days post-injection and decline slowly

Vitamin B12 in health and disease

Interestingly, as predicted by the Igfbp4-ko and the pappa-ko animal models described previously, a human PAPP-A2 gene defect with growth phenotype was recently reported as detailed below (43)

A meta-analysis of patients from two large trials revealed that patients with normal kidney function may benefit from vitamin B12 supplementation for stroke prevention, whereas patients with impaired kidney function may not (235)