how long does vitamin b12 injection stay in your system Shots at Home: How, Where & Often to Inject Yourself how long does vitamin b12

Subcutaneous injection is the most common research-context format today, but no published human pharmacokinetic study has formally characterized subcutaneous AOD-9604 (this gap was specifically called out in FDA's December 2024 review)

Conversely, medications that further slow gastric emptying, such as anticholinergics or opioid analgesics, may exacerbate gastrointestinal adverse effects including nausea, vomiting, and constipation

Additional risk factors include advancing age (due to reduced gastric acid production), excessive alcohol consumption (impairing absorption and storage), and rare genetic disorders affecting B12 transport or metabolism

Some individuals may need B12 supplements if they have certain medical conditions or dietary restrictions, such as those with disease or dietary restrictions

If your levels were low to start, one injection helps refill your tank, and you may feel steadier for a couple of weeks