Your service made it easy to use it again, without having to go to an office 1x week
However, unfortunately, vitamin B12 deficiency is somewhat common, especially in the elderly, strict vegans, and people on antacid medications, so I dont mean to downplay the importance of vitamin B12 or the B vitamins more generally
The frequency depends on your individual needs
However, it may only work if you are deficient or inadequate in vitamin B12 or have a chronic health condition, like myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) or megaloblastic anemia (see next point)
Correcting a choline deficiency, for example, may restore normal liver function but that is a nutrient-correction benefit, not a pharmacological weight loss effect
This often leads to painful and/or disruptive symptoms in the feet and lower legs but these symptoms may also progress to other parts of the body