As of 2015, there is no connection between B-12 shots and weight loss, according to Mayo Clinic. No evidence shows weight loss benefits associated with B-12 shots.
Vitamin B-12 helps the body with the formation of red blood cells and DNA synthesis, as stated by Healthline. The vitamin also assists the body in helping to convert fats into energy. Instead of getting the injection, users can obtain the vitamin from foods such as eggs and dairy products. The National Institutes of Health emphasizes that people over the age of 14 should consume about 2.4 micrograms of vitamin B-12 per day.