The water molecule has two hydrogen atoms, chemically bound to the oxygen atom. This is different from the hydrogen gas molecule (H2), which is just two hydrogen atoms bound only to each other.
For example, we need oxygen (O2) to live, but we can’t get our oxygen from drinking water. That’s because the oxygen is chemically tied up in the water molecule. We need available oxygen gas (O2), a gas that is not bond to other atoms or molecules. We need the available hydrogen gas (H2).
This is why water is not explosive or doesn’t burn. Although it contains hydrogen, which is flammable, and oxygen, which fire needs to burn, the hydrogen and oxygen are bonded together to form water (H2O). This is why water is not flammable. In hydrogen water, the hydrogen that is shown to be therapeutic is the available dissolved hydrogen in its diatomic form, called molecular hydrogen.