[6] [65] Since there are few non-animal sources of the vitamin, vegans are advised to consume a dietary supplement or fortified foods for B 12 intake, or risk serious health consequences
Inhibiting Lipogenesis: This is the process where your body creates new fat

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

This is why many people report feeling a noticeable difference in their energy levels and mental clarity much faster with injections compared to pills
10.1111/scd.12685 15 de BenoistB