Doctors need to think about these differences when planning treatment
You're a strong candidate for B12 injections if you experience any of the following: Persistent fatigue that sleep doesn't fix Brain fog, forgetfulness, or trouble concentrating Low mood, anxiety, or stress that feels disproportionate to what's happening Weight gain or difficulty losing weight despite consistent effort Tingling, numbness, or weakness in hands or feet (signs of B12-related neuropathy) Frequent colds, slow healing, or post-COVID fatigue A plant-based, vegetarian, or vegan diet Age 50 or older (B12 absorption naturally declines with age) A history of gastric bypass, Crohn's disease, celiac disease, or chronic acid reflux Long-term use of metformin (for diabetes), proton pump inhibitors (Prilosec, Nexium), or H2 blockers (Pepcid, Zantac) An MTHFR gene variant or known methylation issue A history of B12 deficiency, pernicious anemia, or low folate Hormonal shifts: perimenopause, menopause, postpartum If you fit one or more of these, a vitamin B12 shot is one of the lowest-risk, fastest-acting interventions available
In some cases, individuals with a deficiency may experience weight loss when they receive vitamin B12 supplementation
Vitamin B12 shots are usually safe, but knowing about possible side effects and problems is key for good care
the serum B12 concentration of a given person may be 240 pmol/l with one assay, and 440 pmol/l with a different assay There is also considerable variability with just one and the same serum B12 assay
