No, you cant overdose, since B12 is water-soluble and any excess will be out in your urine in no time
It depends how low your levels start out
Prez R, Castilla-Cortzar I, Nez M, Prado A, Mirpuri E, Garca M, Gonzlez Barn S, Picardi A: IGF-I does not improve fat malabsorption in cirrhotic rats
However, it does not directly contribute to faster weight loss
Sometimes, you may need additional medical attention or further testing to rule out a more serious underlying condition
P to GSL : Appropriate when the medicine can be sold with reasonable safety outside of a pharmacy environment, meaning the hazard to health, risk of misuse, or need for special precautions is small, and wider sale is a convenience