Glutathione is a naturally occurring antioxidant composed of three amino acids: glutamine, cysteine, and glycine. It plays a key role in cellular defense by supporting detoxification, reducing oxidative stress, and maintaining redox balance. Glutathione is produced in the body but may be affected by factors such as aging, illness, or environmental stressors. It has been studied in the context of liver function, immune support, and overall cellular health.