The Messenger of Allah ﷺ said: There is sexual defilement under every hair; so wash the hair and cleanse the skin. Abu Dawud said: The tradition narrated by Harith b. Wajih is rejected (Munkar). He is weak (in transmission).  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّ تَحْتَ كُلِّ شَعْرَةٍ جَنَابَةً فَاغْسِلُوا الشَّعْرَ وَأَنْقُوا الْبَشَرَ  

the Prophet said: "Under every hair is sexual impurity so wash (all of) the hair and cleanse the skin."  

عَنِ النَّبِيِّ ﷺ قَالَ تَحْتَ كُلِّ شَعْرَةٍ جَنَابَةٌ فَاغْسِلُوا الشَّعَرَ وَأَنْقُوا الْبَشَرَ قَالَ وَفِي الْبَابِ عَنْ عَلِيٍّ وَأَنَسٍ  

"The Messenger of Allah said: 'Under every hair there is the state of sexual impurity, so wash the hair and cleanse the skin.'"  

قَالَ رَسُولُ اللَّهِ ﷺ إِنَّ تَحْتَ كُلِّ شَعَرَةٍ جَنَابَةً فَاغْسِلُوا الشَّعَرَ وَأَنْقُوا الْبَشَرَةَ  

"إِنَّ تحْتَ كلِّ شَعْرةٍ جَنابةً، فَاغْسِلوا الشَّعْر، وأَنْقُوا الْبَشْرَةَ" .  

"تَحْتَ كُلِّ شَعْرَة جَنَابَةٌ".