It is better not to heat our formula in the microwave. The disadvantage of the microwave is that the bottle does not heat up evenly and there is a good chance that the bottle will become too hot. And that is not good for the quality, which we have done our best.
We do not recommend reheating cooled formula, because freshly prepared formula is simply better: a bottle must be drunk within an hour, otherwise it's better to throw it away and start over.
Pre-boiling the water in the microwave is of course possible. And then of course let the water cool down to about 40°C before adding our powder.