The Prophet ﷺ said, "The best things with which you can change gray hair are henna and katam."
أخبرنا محمد بن مسلم قال حدثنا يحيى بن يعلى قال حدثنا به أبي عن غيلان عن أبي إسحق عن ابن أبي ليلى
عن النبي ﷺ قال أفضل ما غيرتم به الشمط الحناء والكتم
No references are available.
[Sahih] It is also in Kubra, no. 9349, and the hadith has corroborating narrations, including the one that follows. Muhammad bin Muslim is Ibn Warah, and Ghaylan is Ibn Jaami. Abu Ishaq narrated using "an" (indicating a possible break in the chain), and Ibn Abu Layla is Abdul-Rahman.