Free radicals and oxidants have dual roles in the body, being both harmful and beneficial. They are produced through normal metabolism or external sources like pollution, cigarette smoke, and radiation. When free radicals accumulate, they cause oxidative stress, linked to chronic diseases such as cancer, autoimmune disorders, and neurodegenerative diseases. The body produces antioxidants, either naturally or from diet, to counteract oxidative stress by neutralizing free radicals and repairing damage. Free radicals include reactive oxygen species (ROS) and reactive nitrogen species (RNS), which can be harmful in excess but beneficial at low levels. They are formed through enzymatic and non-enzymatic processes, including redox reactions and oxidative phosphorylation. ROS and RNS are involved in immune defense and cellular signaling but can cause oxidative stress when excessive, leading to damage to cell structures like DNA, proteins, and lipids. Antioxidants, both endogenous and exogenous, help neutralize free radicals and prevent oxidative damage. They include enzymes like superoxide dismutase, catalase, and glutathione peroxidase, as well as non-enzymatic antioxidants like vitamins C and E, beta-carotene, lycopene, selenium, and flavonoids. These antioxidants play a crucial role in preventing and repairing damage caused by oxidative stress. Antioxidant supplementation can offer health benefits but must be approached cautiously due to potential pro-oxidant effects at high doses. While dietary antioxidants are generally safer and more effective, supplements may be necessary in specific cases. However, excessive intake can lead to adverse effects, and the long-term benefits and risks of antioxidant supplements remain debated. Oxidative stress is implicated in various diseases, including cancer, cardiovascular disease, neurological disorders, and chronic kidney disease. Antioxidants are essential for maintaining health, and a balanced diet rich in fruits, vegetables, and omega-3 fatty acids is recommended to support antioxidant defenses. Lifestyle choices, such as avoiding smoking and excessive alcohol consumption, are also crucial in reducing oxidative stress.Free radicals and oxidants have dual roles in the body, being both harmful and beneficial. They are produced through normal metabolism or external sources like pollution, cigarette smoke, and radiation. When free radicals accumulate, they cause oxidative stress, linked to chronic diseases such as cancer, autoimmune disorders, and neurodegenerative diseases. The body produces antioxidants, either naturally or from diet, to counteract oxidative stress by neutralizing free radicals and repairing damage. Free radicals include reactive oxygen species (ROS) and reactive nitrogen species (RNS), which can be harmful in excess but beneficial at low levels. They are formed through enzymatic and non-enzymatic processes, including redox reactions and oxidative phosphorylation. ROS and RNS are involved in immune defense and cellular signaling but can cause oxidative stress when excessive, leading to damage to cell structures like DNA, proteins, and lipids. Antioxidants, both endogenous and exogenous, help neutralize free radicals and prevent oxidative damage. They include enzymes like superoxide dismutase, catalase, and glutathione peroxidase, as well as non-enzymatic antioxidants like vitamins C and E, beta-carotene, lycopene, selenium, and flavonoids. These antioxidants play a crucial role in preventing and repairing damage caused by oxidative stress. Antioxidant supplementation can offer health benefits but must be approached cautiously due to potential pro-oxidant effects at high doses. While dietary antioxidants are generally safer and more effective, supplements may be necessary in specific cases. However, excessive intake can lead to adverse effects, and the long-term benefits and risks of antioxidant supplements remain debated. Oxidative stress is implicated in various diseases, including cancer, cardiovascular disease, neurological disorders, and chronic kidney disease. Antioxidants are essential for maintaining health, and a balanced diet rich in fruits, vegetables, and omega-3 fatty acids is recommended to support antioxidant defenses. Lifestyle choices, such as avoiding smoking and excessive alcohol consumption, are also crucial in reducing oxidative stress.