Vitamin B₁₂ has the function of preventing anemia, nourishing the nerves, promoting sleep, promoting metabolism and so on. 1. Prevent anemia: Vitamin B₁₂ can promote the development of red blood cells, thereby preventing anemia. 2. Nutritional nerves: Vitamin B₁₂ can nourish the nerves and promote nerve fiber repair. 3. Promote sleep: Vitamin B₁₂ can play a role in promoting sleep, improve the quality of sleep, and can alleviate the symptoms of excessive dreaming. 4. Promote metabolism: Vitamin B₁₂ can promote the body’s metabolism of fatty acids, which enables the body to use fats, carbohydrates, proteins and other substances. There may be adverse reactions such as hypokalemia and hyperuricemia when taking it. Contraindications are not clear, when the body lacks Vitamin B₁₂, it is recommended to take Vitamin B₁₂ supplementation under the guidance of a doctor, and it is not advisable to take supplementation on your own.