Sunan an-Nasa'i, Book 48, Hadith 43 (In-Book) ⓘ
It was narrated from 'Abdullah bin Buraidah that: He heard that the Messenger of Allah [SAW] said: "The best things with which you can change gray hair are Henna and Katam."
أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا الْمُعْتَمِرُ، قَالَ سَمِعْتُ كَهْمَسًا، يُحَدِّثُ عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " إِنَّ أَحْسَنَ مَا غَيَّرْتُمْ بِهِ الشَّيْبَ الْحِنَّاءُ وَالْكَتَمُ " .
also referenced under: Hadith 5082 (Reference) & Volume 6, Book 48, Hadith 5085 (DarusSalam)