Athletes, Coaches, Health Professionals, and Support Personnel Additional Prohibited List Information Athlete Guide to Anti-Doping A directory of articles written by USADA, covering many substances and methods listed in The Prohibited List
It's recommended that your provider give you a test dose of cyanocobalamin before starting treatment to determine whether you're at risk of having an allergic reaction to the medication
Or put another way More is not better
How Vitamin B-12 Injections Works
Ferlay J, Colombet M, Soerjomataram I, Parkin DM, Pieros M, Znaor A, Bray F (2021) Cancer statistics for the year 2020: an overview
To understand the comparison, you have to look at their structural origins