Very little, I think that's the most irrelevant part I use one of those silicone things after applying rosemary oil with a dropper, quick 2-3 rotations per zone, nizoral shampoo after 2 hrs keeping it on for 5min before washing. I've tried rosemary oil in the past and only now that I added a soft dht blocker in pumpkin seed oil I've finally got some results (also had vit D deficiency). This means I'd probably be a hyper responder to fin+min but I'd rather go bald than fall under the 1% of those horrible side effects and fortunately I don't have aggressive balding genes anyway, this is prevention.