I have self-injected B12 (and Vit D3, separately of course) through i.m. route for years with no problems. Because my terminal ileum was removed during the j-pouch surgery, I am always low in B12 unless I self-inject it every three months. In my country, it is much less expensive and much more efficient than other forms of administration. However, I would not recommend it if you have zero experience. You may need a nurse to give you some sort of training at least.