monthly b12 injection black eyes Under-Eye Dark Circles: Causes, Treatments, and Prevention Tips Vitamin B12 deficiency - Wikipedia

Can COVID-19 immunisation cause subacute thyroiditis

StatPearls (US source) states, Patients generally receive lifelong intramuscular (IM) injections of vitamin B12 (typically 1000 g per month)

Left untreated, B12 deficiency can lead to irreversible neurological damage, making early recognition and intervention essential

Possible adverse effects may include: Injection site reactions : Redness, swelling, irritation, or discomfort Gastrointestinal symptoms : Nausea, vomiting, stomach cramps, or diarrhea Headaches or dizziness Allergic reactions : Rash, itching, shortness of breath, or facial swelling (rare) Increased heart rate or anxiety (typically temporary from B-vitamins) Fatigue or weakness if used improperly Elevated liver enzymes when taken in excess particularly with methionine or choline Insomnia if taken late in the day due to increased energy levels Who should avoid or use caution