The B12 Shot: What Every Human Needs to Know About Injectable Vitamin B12 Top 5 Vitamin Injections & Their Uses, These injections help treat vitamin deficiencies and support overall health., 1 Vitamin B12 Injection Helps in nerve weakness & deficiency, 2 Vitamin D3 If you have a low vitamin B12 level, injections can go a long way toward improving your health and well being. But if your B12 level is normal, don't fall for claims that B12 Shots at Home: How, Where & How Often to Inject Yourself AZ IV Medics