You can use the Derma Roller before or after applying the Hair Growth Serum/Tonic. If you have long hair, it is best to part your hair where you are rolling. Start at the front hair line and roll to the back of the hair at the crown. It’s also best to go across this area diagonally as the more directions you do it the better. Make sure you concentrate on any area you are losing hair. Pay particular attention to the crown of the head as this is where most people will lose hair but are unable to see it.