[Routine Help] Which TO retinol/retinoid should I use on my legs?

Beauty Tips For Body Care
I have some old scars on my legs that I would like to fade with a retinoid or retinol but I'm not sure which one to use. Obviously a higher concentration is better since the skin on your legs is thicker than the skin on your face but I don't know what % is enough.
Girls Blog 2015
Submitted by humblebumble99