Molecular hydrogen fights free radicals in your body and protects your cells from the effects of oxidative stress. There have been studies done, where it shows hydrogen water experienced decreased levels of hydroperoxide which is a marker of oxidative stress. Some research shows that hydrogen water may be effective at reducing markers of oxidative stress and improving risk factors related to metabolic syndrome. It can reduce your bad cholesterol and increase your good cholesterol. Also, It's great for athletes. It can reduce your blood lactate, and decrease muscle fatigue. Though some research on the health effects of hydrogen water shows positive results, larger and longer studies are needed before conclusions can be drawn. It has been approved by the FDA, and not shown to cause harm.