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.Here’s an example: we need oxygen (O2) to live, so why can’t we just get our oxygen from drinking water, H2O? It’s because the oxygen is chemically tied up in the water molecule. We need available oxygen gas, (O2) that is not bound to other atoms or molecules. In the same way, in order for the dissolved hydrogen gas (H2) to benefit us, it must be in an unbound form, and therefore available for therapeutic benefit.