Boiling cold water vs running it til hot comes out

which is more energy effecient, boiling the cold water, or running it out until hot water from the water heater comes out(wasting water in the process)?

According to

It is cheaper to boil the jug to wash a few dishes than it is to fill the sink with water from the hot tap.

Depending on where your water heater is there can be many litres of hot water in the pipes by the time hot water comes out of the tap. All that water then goes cold.

We need more information.

It all depends on your source of energy. In North America it is common for your hot water tank to be fueled by natural gas, or perhaps even oil, and for your stove to be electric. You don’t give us your fuel source, nor your location.

Then again, you could have propane for one or the other.

I use electricity for both; most people in urban centres don’t.