Vitamin B6 is a water-soluble vitamin essential for good health. Vitamin B6 is involved in fat and protein metabolism as well as the conversion of carbohydrates into simple sugars used by the body for energy. Vitamin B6, or pyridoxine, is utilized by more than 100 enzymes required in protein metabolism. It is involved in the production of neurotransmitters. It is required to produce serotonin that helps mood. According to the University of Maryland Medical Center, vitamins B6 and B12, in conjunction with Vitamin B9 (folic acid), help control the levels of homocysteine in the blood. High levels of homocysteine are linked to cardiovascular disease. Studies show that vitamin B6 given intramuscularly as an injection is also used to reduce nausea and vomiting in pregnancy. This injection can be used for mood, energy and metabolism.