B-complex vitamins comprise eight water-soluble compounds (thiamine/B1, riboflavin/B2, niacin/B3, pantothenic acid/B5, pyridoxine/B6, biotin/B7, folate/B9, cobalamin/B12) essential for energy metabolism, red blood cell formation, and neurological function. Vitamin E refers primarily to alpha-tocopherol, a fat-soluble antioxidant protecting cell membranes from oxidative damage. These vitamins occur naturally in foods such as grains, meats, leafy greens, nuts, and vegetable oils. They are commonly used in dietary supplements and food fortification. Individual compounds exhibit distinct structures and properties; B vitamins are generally polar while Vitamin E is lipophilic. Excessive intake of certain B vitamins or high-dose Vitamin E may cause adverse effects, though they are considered safe within recommended dietary allowances.