Anything systemic such as a rash, hives, dizziness, or trouble breathing is rare, but stop and seek care if it happens
"Nutritional Requirements of Pigs - Management and Nutrition"
Biochemistry 57 , 827838 (2018)
chronic liver disease and hepatitis may present with elevated levels Renal impairment : Reduced clearance can contribute to accumulation, though this is rarely clinically significant Solid tumours : Certain malignancies, particularly hepatocellular carcinoma and metastatic disease, may elevate B12 levels [3] Evidence suggests that unexplained markedly elevated B12 levels without supplementation may sometimes be associated with underlying disease
Injections require more setup: sterile supplies, proper injection technique, and site rotation to avoid irritation
Self, like Andrew Hiller, received the sanction for discussing the use of a banned substance on various podcasts