Jaabir bin Samurah R.A. was asked:
"Were there any white hair in the blessed head of Rasulullah (Sallallahu alaihe wasallam)? He replied: 'He only had a few on the middle parting, and when Rasuullah (Sallallahu alaihe wasallam) oiled his hair, they did not show'". (ES)
English reference (ES): Book 5, Hadith 43 (ES)
Arabic reference (ES): Book 5, Hadith 44 (ES)