The dose and duration will depend on what you are using it for and how well it helps your symptoms
Efficacy and Safety of Ultrahigh-Dose Methylcobalamin in Early-Stage Amyotrophic Lateral Sclerosis: A Randomized Clinical Trial
Summary: Excessive vitamin B12 intake rarely causes toxicity, but very high levels from supplements or injections may be associated with skin reactions such as acne-like eruptions, though serious adverse effects remain exceptionally uncommon
Br J Dermatol
In diet-induced obese (DIO) mouse models, 5-Amino-1MQ treatment produced significant reductions in body weight, white adipose tissue mass, and adipocyte cell size without significant effects on food intake suggesting a metabolic rather than appetite-suppressing mechanism
One common question that arises is, "How long do the benefits of a vitamin B12 injection last?" The answer can vary from person to person based on factors such as metabolism, overall health, and the severity of B12 deficiency