They might start with higher doses to fill up their B12 stores
Other effects require reporting to a medical team as soon as possible, including: An allergic reaction, including rashes, itching, hives, and a swollen face, tongue, throat, or lips High blood sugar symptoms Other liver damage symptoms, including pain in the upper-right abdomen, appetite loss, dark yellow urine, a yellow tint in the skin or eyes known as jaundice, and feeling unusually weak or tired Tingly, numb, or painful feet Following a balanced diet means that most people are unlikely to develop a B vitamin deficiency
Casella EB, Valente M, de Navarro JM, Kok F
B12 is a water-soluble vitamin, which means your body doesn't store large amounts of it and typically removes any excess amounts when you pee