This is all very difficult to answer, because the internet forum dermarolling procedure is predicated on this study, and avoiding the question of whether or not dermarolling is effective (which I think is the first question one should care to answer before proceeding), the study itself leaves a lot of holes in its procedures. This left random forum folks to fill in holes. For example, the researchers noted that they only rolled on an area of skin until it turned red, before moving on to the next section of scalp. Is that a good guide for how many passes one should make? I don't know. A lot of folks advocated rolling until moderate blood was drawn, but again, there aren't documented best practices for efficacy.
In the study, subjects who received dermarolling treatments did so on a weekly basis. They also applied 5% minoxidil to the shaven scalp twice a day.
Finally, they sterilized the shaven scalp of the participants and the dermaroller with betadine before each use. Please do not rely on water to sterilize a medical instrument.
1.5MM once a week, sterilized, nice and deep. There was also a member who had success at .5MM every 5 days (deep) but he had a very complicated regimen as well.
There are arguments that vary from not applying any anti-inflammatories anywhere between a few hours to a few days after rolling.
I personally think that protein and supplementation post-rolling (just as you would when working out a muscle group) is something that many folks are missing. You can break down a body part all you want, and yes the body will release some natural growth factors, but if you don't give it the building blocks it needs (protein) to rebuild cells, then you probably won't be getting very far.
