I have great respect for Dr. Fernandes and I am not sure whether microneedling was already widely used by the time he made the "no serious bleeding, no results" statement but current reality does not support that statement. Almost nobody rolls at home with a 3 mm dermaroller, causing so much blood as seen on the attached photo (a 3 mm roller is used), and still there are thousands of "homerollers" reporting great results and backing it up with before-and-after pictures. It may perhaps take a little longer with needles shorter than 3 mm, but in return for a little extra patience you get the peace of mind that there is a no danger for infection, which with 3 mm is starting to become a small risk factor.
Just one example concerning success with a 1 mm roller size:
https://http://forums.owndoc.com/dermarolling-microneedling/improvement-after-dermarolling/Dr. Fernandes rolls his patients (or at least some of them) with a 3 mm dermaroller but he also promotes and uses on himself shorter sizes – such as 1 mm and others.
Skin thickness varies depending where on the body it is (the thinnest skin is on the eyelids, the thickest is on the foot soles) and it also varies individually but it is on average between 1 - 2 mm thick.
A dermastamp penetrates deeper than a dermarolloller of the same needle length (unless you push the roller into the skin with very much force).
A 1.5 mm dermastamp normally penetrates about as deep as a 2 mm dermaroller.
A 2 mm dermastamp will normally penetrate slightly less than a 3 mm dermaroller.
If you read the size guide in our dermarolling instructions, you will notice that I tend to recommend a combination of a dermaroller and a dermastamp (or a single needle) for scars and wrinkles – a dermaroller for an overall roll and a dermastamp to locally target individual scars and wrinkles.
In case the scars or wrinkles do not respond to microneedling, it is a good idea trying longer needles (or/and applying Tretinoin right after microneedling or/and adding the suction method etc. but rolling large areas at home with a 3 mm size dermaroller and inducing such bleeding as seen on the photo carries more risks, is painful and it is not really necessary from our experience.
I have gotten many emails from people (living in various countries) who underwent a professional dermrolling treatment by plastic surgeons and the needle length used was usually a 1.5, maximum 2 mm.
I have answered a similar question here:
https://http://forums.owndoc.com/dermarolling-microneedling/the-more-blood-the-better-when-dermarolling/Related forum postings:
https://http://forums.owndoc.com/dermarolling-microneedling/do-we-need-to-get-that-bloody-to-get-results/BTW a dermaroller was already patented in 1975 by Dr.Pistor:
https://http://www.owndoc.com/pdf/dermaroller-patent.pdf