Antioxidants are substances that can freely neutralize radicals (they can convert them into less reactive states) and thus eliminate their harmful effect. Free radicals are molecules that contain a free electron pair, which makes them very reactive. These highly reactive molecules then pull electrons out of other compounds, damaging our body's cells.

Oxidative stress is caused by the presence of harmful oxygen radicals (reactive oxygen species). Among the strongest antioxidants we can include glutathione or its precursor NAC or astaxanthin.