Vitamin C, or L-ascorbic acid, is a water-soluble essential nutrient and potent antioxidant vital for human physiology. It serves as a cofactor in collagen synthesis, carnitine production, and neurotransmitter biosynthesis. The compound features a five-membered lactone ring with enediol functionality enabling its reducing and free-radical scavenging properties. Abundant in citrus fruits, peppers, and leafy greens, it prevents scurvy by maintaining connective tissue integrity and enhances non-heme iron absorption. Chemically unstable in neutral or alkaline solutions, heat, light, or oxygen, it degrades readily. Widely used as a food preservative and dietary supplement, it supports immune modulation and wound healing. Its bioavailability is high via active transport in the intestine.