Polarized light micrograph of vitamin C crystals, ascorbate or ascorbic acid, an essential nutrient for humans. It has a key role in the synthesis of collagen, carnitine, norepinephrine, peptide hormones, tyrosine, catecholamine, and bile acid. It is involved in the metabolism of microsomes, iron absorption, carbohydrates, and cellular respiration. Being the most potent antioxidant, it protects against oxidative stress and free radicals. Its main natural sources are fresh fruits and vegetables. It is industrially produced from glucose, and included in fungicides, pesticides, and as an antimicrobial and antioxidant in foodstuffs. Medical uses: ascorbic acid deficiency, scurvy, burns, iron nutrition, wound healing, immune system, and cancer prevention. It also lowers the risk of strokes, Alzheimer??? disease, and Parkinson??? Disease. Field of view size: 5.88 x 8.83 mm (0.23 x 0.35 in)