Do "piggy-backs" cause hair growth?
Not usually! I enjoyed this article which showed piggyback can cause hair growth if you are 9 months old & grandpa is using minoxidil (Rogaine).
Farsani et al. Piggyback acquired hypertrichosis. Pediatr Dermatol 2014. 31(4):520
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Vancouver office at 604.283.9299