Sunan an-Nasa'i 5056
سنن النسائي#5056Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ بَشَّارٍ، قَالَ حَدَّثَنَا أَبُو دَاوُدَ، قَالَ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ، عَنْ قَتَادَةَ، عَنِ الْحَسَنِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم نَهَى عَنِ التَّرَجُّلِ إِلاَّ غِبًّا .
It was narrated from Al-Hasan that:The Prophet [SAW] forbade coming one's hair except every other day
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Abu Ghuddah, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 48:17