b12 injections in cat Cyanocobalamin Injection, 1000 mcg/mL 1mL Vial Vitamin B12 Deficiency in Cats:
Description
Many prenatal vitamins contain all three [*]
This reaction appears to occur at neutral or alkaline pH

31G is thinner than 18G)
Though anecdotal reports are common, large-scale human trials remain limited, highlighting the need for further scientific validation

You may not even need to pinch the skin, though doing so is still good practice
