Route/evidence mismatch: the pivotal mouse study tested subcutaneous injection at a fixed research dose (20 mg/kg, three times daily) the oral capsule use that is actually sold and discussed commercially has not itself been directly tested in that published research
Proponents of B12 shots claim they turbocharge the metabolism (read: make you thinner), strengthen the immune system, and help cure fatigue, insomnia, even depression
Improved Mood and Mental Health: B vitamins play a vital role in maintaining neurotransmitter synthesis, promoting a balanced mood, reducing stress, and supporting optimal brain function
Most begin to save money, comply with the law or because their customers demand it so give them what they want and make it easy for them to buy from you
While no mechanism suggests delayed toxicity, this cannot be completely ruled out without long-term controlled studies