Folic Acid (Folate or Folacin)
It works closely with B12. It is needed for the proper formation of the red blood cells. It has the ability to lower the levels of homocysteine. Its addition results in the reversal of dysplasia. Oral contraceptives cause a localized folate deficiency in the cell of the cervix, making them susceptible to cancer-causing viruses or chemicals.
It has the ability to prevent defects of the neural tube, the structure in the embryo that gives rise to the brain, the spinal cord, and other parts of the nervous system. Because folic acid derivatives are coenzymes for neurotransmitters its presence help improve mood, arousal, and cognitive and social function. Also people with vitiligo showed improvement with addition of B12 and Vitamin C.
Required during high levels of stress, ability to rescue chemotherapy patients and as the ability to regenerate a brain chemical called SAMe.

Food Sources
Beef liver, lamb liver, pork liver, and chicken liver; deep green leafy vegetables, such as spinach, kale, and beet greens; asparagus, broccoli, whole wheat, and brewers yeast.

No Toxicity known. Always take B12 with folate.