self administer intramuscular thigh vitamin b12 injection site How to self-inject - Overview B12 Injections at Home -

However, full replacement of the circulating red cell pool takes approximately eight to twelve weeks , reflecting the normal red cell lifespan

This allows it to effectively talk to all three at once, leading to its powerful effects on weight loss and blood sugar control

The target range is 2-8 degrees Celsius (36-46 degrees Fahrenheit)

These are two different timelines

PMC 7601760

B12 is a water-soluble vitamin your body uses to: Make red blood cells (which carry oxygen to your tissues) Keep your nervous system functioning properly Help your body turn food into usable energy Your body can't make B12 on its own you get it from animal-based foods (meat, eggs, dairy) or supplements