Ergothioneine (EGT) is a unique sulfur-containing amino acid that functions as a potent intracellular antioxidant. Naturally derived from fungi and some bacteria, it is not synthesized in the human body but is actively transported into cells via a specific transporter (OCTN1/SLC22A4). EGT has gained attention for its role in protecting mitochondria, DNA, and other cellular components from oxidative damage—a key driver of aging and chronic disease