When the Messenger of Allah ﷺ took a bath because of sexual intercourse, he poured three handfuls of water upon his head. Hasan b. Muhammad said to him (the narrator): My hair is thick. Upon this Jabir observed. I said to him: O son of my brother, the hair of the Messenger of Allah ﷺ was thicker than your hair and these were more fine (than yours). (Using translation from Muslim 329)
كَانَ رَسُولُ اللهِ ﷺ إِذَا اغْتَسَلَ مِنْ جَنَابَةٍ يَصُبُّ عَلَى رَأْسِهِ ثَلَاثَ حَفَنَاتٍ فَقَالَ لَهُ الْحَسَنُ بْنُ مُحَمَّدٍ إِنَّ شَعْرِيكَثِيرٌ قَالَ يَا ابْنَ أَخِي كَانَ شَعَرُ رَسُولِ اللهِ ﷺ أَكْثَرَ مِنْ شَعْرِكَ وَأَطْيَبَ