The Messenger of Allah ﷺ had only about twenty grey hairs.
حدثنا محمد بن عمر بن الوليد الكندي حدثنا يحيى بن آدم عن شريك عن عبيد الله عن نافع
كان شيب رسول الله ﷺ نحو عشرين شعرة
No references are available.
[Sahih] Tirmidhi transmitted it in Shamail, no. 40, from Muhammad bin Umar, and Busiri graded it sahih, and the preceding hadith serves as corroborating evidence for it.