Antioxidants and phytonutrients are plant-derived compounds that combat oxidative stress, reduce inflammation, and support overall health. Our comprehensive guide covers powerful antioxidants including glutathione and vitamin C, colorful carotenoids like astaxanthin and lutein, diverse polyphenols and flavonoids from berries and tea, specialized plant compounds including terpenoids and alkaloids, and concentrated herbal extracts. Explore how these compounds neutralize free radicals, support cardiovascular and brain health, enhance immune function, and may reduce disease risk. Learn about food sources rich in phytonutrients, understand antioxidant capacity measurements, and discover evidence-based supplementation strategies for optimal antioxidant protection and cellular health.