Pernicious anemia
No. Vitamin B12 injections will not accomplish this result.
Cyanocobalamin injections are used to prevent a lack of vitamin B12 in the patient. It is usually used on patients who cannot otherwise absorb the vitamin B12 through the intestine.
Many people who are looking to lose weight quickly turn to vitamin B12 injection weight loss. These injections directly into the bloodstream promote weight loss by speeding up the metabolism and suppressing appetite. Vitamin B12 injection weight loss often occurs more quickly than with diet and exercise alone. Many people get regular injections of this powerful vitamin supplement to fuel workouts and burn more calories. In addition, vitamin B12 injections for weight loss help the body continue to burn calories long after the workouts have been completed. Vitamin B12 injections for weight loss are often available from bariatric surgeons who specialize in weight loss.
Jaundice
Some athletes believe that vatamin B12 injections will increase oxygen supply to the muscles. But according to a Wichita Eagle article - The absence of a vitamin B12 deficiency does not support this.
There are a number of benefits of B12 injections, these include but are not limited to; increase in metabolism, energy boosts, mood boosts and increased cardiovascular performance.
You can find out more about it here: www.mayoclinic.com/health/vitamin-b12-injections/AN01400. Please be sure to check with your doctor to see if it is right for you.
B12 is a vitamin
If you are referring to vitamin b12, vitamin b12 is healthy for you.
The Mayo Clinic provides a discussion of the effectiveness of B12 weight loss, which consists of injections of Vitamin B12. The general consensus is that these injections don't really work, and instead are marketed inaccurately as a cheap and easy solution. You're better off maintaining a healthy lifestyle and diet.
It's hard to know with such little information, but probably because of a severe lack of vitamin B. It could be for some sort of neurological regeneration. Or, it could be used to loose weight. You probably should ask your doctor.
Prescriptions are required in the United States for b12 injections. Most people get the required amount of B12 in their diets, however there are some people that have pernicious anemia that require b12 injections.