New collagen formation is at a depth of 0.6 mm and goes towards the surface of the skin [2012]. No new collagen fibers could be found deeper than 0.6 mm [2008].
Most newly built elastin fibers are at a depth of 0.6 mm and no changes were seen deeper than .6 mm [2011].
The above show that 0.6 mm is the sweet spot, though there are 2 things to keep in mind:
1- The magic may be occurring at 0.6 mm, but you have to get the needle deeper than that to cause that 0.6 mm impact.
2- If you use a dermaroller you are likely not going the full depth of the needle, it depends on how hard you push. Whereas you are going the full depth of the needle on a derma-gun or derma-stamp.
In the 2011 study above, the dermaroller was penetrating approximately 1 mm.
In the 2008 study above, they concluded that using 1 mm dermaroller, they had similar results to the 1996 pioneering work on dermarollers in which 3 mm was used.
0.5 mm dermaroller is the minimum length needed to produce collagen.
As such, we recommend using between a 0.5 mm dermaroller and a 1 mm dermaroller. Any shorter than 0.5 mm will have no effect; any longer than 1 mm is just causing extra pain for no additional gain.