I've been using Minoxidil for about 2 months and 1 week, and dermarolling once a week for the last 4 weeks. It should not cause you to shed. You'll want to use a .5 length roller, and you shouldn't apply minoxidil until 12-24 hours after rolling. (I'll explain why I said 12-24 hours) For the first 3 weeks I derma rolled on Tuesday morning, so what I do is apply my monday night minoxidil, then wake up Tuesday and derma roll. Then I wait until the following day before applying minoxidil again. The reason at the beginning is that once you dermaroll you are creating tiny puncture wounds in the scalp and applying minxoxidil into those wounds too soon after could cause too much Minoxidil getting into bloodstream. After a few weeks of getting used to it I started applying my Minoxidil on late Tuesday evenings after a good 12-14 hours has elapsed. I will tell you, derma rolling does cause a bit of tenderness on your scalp. You dont want to draw blood, but you want to create some redness which signifies wounding, which theoretically causes the follicles to get more blood, collegen to form, and healing and scalp circulation.