https://onlinelibrary.wiley.com/doi/abs/10.1111/jocd.13714
I'm not convinced at all. No quantitative data is provided, and their results contradict themselves. Hair thickness with .6mm was significantly greater than control, but not significantly greater than 1.2mm, however 1.2mm was not significantly different from control.
What's clear is there was no difference in hair count versus minoxidil monotherapy. This protocol did not induce neogenesis, therefore it is not the optimal protocol. I don't think they wounded as densely as Follica. I think they may have had somewhat better results with .6mm due to the small sample size, and they were basically just wounding for growth factor upregulation versus neogenesis. In my view the greatest takeaway from this study is that you have to wound intensely to trigger neogenesis, otherwise you are better off lightly needling with .5mm daily for absorption and growth factor upregulation.
Here is the study they base their speculation on regarding trauma to the hair bulge:
https://pubmed.ncbi.nlm.nih.gov/21070465/
This study contradicts that:
http://drcarloswesley.com/T/06082014.pdf
I don't think you can compare the depth at which you would cut existing, healthy hairs for transplantion to the depth at which you would wound to induce recruitment of stem cells for neogenesis. For this purpose, damaging the bulge would seem to be beneficial. Also, the hairs that we are trying to thicken are not as deep as the healthy hairs being transplanted. Vellus hairs are around .5-1mm deep. You are absolutely traumatizing the hell out of the bulge in these hairs at any depth. Once again, I think we're left with more questions than answers.
View attachment 145670
Principles and mechanisms of regeneration in the mouse model for wound‐induced hair follicle neogenesis
I will continue wounding at a minimum depth of 1mm.