are b12 injections given in the muscle Injecting Best Vitamin B12 Injection Site:

It just goes to show that the 'B12 deficiency is unlikely in someone so young' is probably right most of the time, but not always

The proper dose of B12 to stay healthy Those who are likely to need B12 shots include people with the aforementioned symptoms as well as those with illnesses like pernicious anemia, atrophic gastritis, infertility, heart palpitations, celiac disease, Crohns disease, pancreatic insufficiency, or AIDS

Most people feel a lift after a B12 shot, but a minority feel briefly worse

Studies confirm 50% drops by midlife, linking to aging symptoms.[1][9] Restoring NAD+ has been shown in animal studies to improve lifespan and healthspan, with human trials indicating benefits in muscle function and cognitive performance

Payer-specific billing rules change with every contract renewal and policy update cycle

Some people may show results in a matter of days, while others may need several weeks or even months