67 years old with thinning skin. Can I use the Derma Roller and get good results or am I past it?

In my opinion, the Derma Roller would still be a benefit for you. It is important to combine the Derma Roller with growth factor serum. Also be careful that you're not using a roller that is thicker than .25 millimeters. There is a significant chance of bleeding and side effects. Hope this helps. Good luck.

How effective rollers are will be determined by your end goal, severity of your loss of collagen, technique, depth of rolling, and frequency. Derma Rollers do work, however they are almost 2 decade old, stamping technology with growth factors is the next step, and then energy based needling with PRP the step above. Attached a video on 'how to'cheersDr Davin Lim Laser and aesthetic dermatologistBrisbane, Australia. 

Micro-needling combined with a human growth factor serum can improve the appearance of the skin at almost any age. Our patients also use
ProCell Therapies growth factor serums at home after their office
treatment and we have been getting excellent results for facial skin
rejuvenation, improving stretch mark scars, and regrowth of scalp hair using
human growth factor hair serums.