For individuals receiving B12 injections for severe deficiency, there have been isolated reports of hypokalaemia (low potassium) during initial treatment, as rapid cell production consumes potassium
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Last reviewed: April 2026 Next scheduled review: October 2026 (FY2027 update) Ready to turn this knowledge into a credential
Other possible vitamin B12 shot side effects include: Headache Dizziness Rash Facial flushing Skin redness Cold symptoms Anxiety Swelling Diarrhea Vomiting High blood pressure How to Prevent The best way to avoid the potential side effects of too much vitamin B12 is to get the majority of your vitamin B12 from nutrient-rich food sources, including meat, poultry, seafood and dairy products
Individuals who feel well-nourished and energetic are more likely to adhere to treatment regimens and maintain healthy lifestyle changes
The mechanism involves an increase in GLUT4 transporter expression, improving glucose uptake