Folate

Folate (vitamin B9) is a water-soluble vitamin essential for one-carbon metabolism, DNA synthesis, and amino acid metabolism. Folate is critical for rapidly dividing cells, including hair follicle matrix cells. The synthetic form (folic acid) is used in supplements and fortified foods, while 5-methyltetrahydrofolate (5-MTHF) is the biologically active form. Individuals with MTHFR polymorphisms may benefit from methylfolate supplementation. Folate deficiency can cause megaloblastic anemia and is well-established as a cause of neural tube defects during pregnancy.