Assalaamu alaykum Shaykh. In our area, many women and girls collect and save their hair that has fallen while combing or after cutting and then sell it to a trader who buys hair in return for some money. Is one allowed to do so?
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
This is impermissible in Islam. It is impermissible to sell any part of the human body, whether that be the hair or any other part. Al-Majmoo' reads, “What is impermissible to sell while attached to the body is impermissible to sell when detached from it, such as human hair.”
The Maaliki scholar Al-‘Adawi wrote, “Imaam Maalik was once asked about the ruling on selling human hair that has been shaved from people's heads. He disliked it.” [Haashiyat Al-‘Adawi ‘ala Sharh Mukhtasar Khaleel by Al-Kharashi]
The prohibition is more emphasized and the sin is graver if these women sell the hair so that others may use it as hair extensions because it is prohibited to extend the hair artificially and it is considered a grave sin. Moreover, selling the hair to women who use hair extensions constitutes cooperating in doing a sin. Allaah, The Exalted, says (what means): {...And cooperate in righteousness and piety, but do not cooperate in sin and aggression...} [Quran 5:2]
Allaah knows best.
You can search for fatwa through many choices