Is L-Cysteine from avian origin Halal?

In the Name of Allah, the Most Gracious, the Most Merciful.

As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.

L-Cysteine is an amino acid used to extend shelf-life in commercial products. L-Cysteine is derived from human hair as well as duck feathers, cow horns and pig bristles.^[1] L-Cysteine can also be sourced from microbial or other synthetic processes.^[2]

It is not permissible to consume any product which contain L-Cysteine made from human hair or from pig bristles.

However, it is permissible to consume L-Cysteine or any products which contain L-Cysteine if it is made from any animal besides pig whether that animal was slaughtered according to the Shar’ee rights of Zabah or not. This is due to the fact that L-Cysteine is made from hair or feathers which do not have life in them.^[3]

It is permissible to consume products that have L-Cysteine from avian origin i.e. L-Cysteine from birds.

For more detail you may refer to: http://askimam.org/public/question_detail/21257

And Allah Ta’āla Knows Best

Mudassir Benish

Student-Darul Iftaa
Houston, TX, U.S.A

Checked and Approved by,
Mufti Ebrahim Desai.

^[1]https://www.vice.com/en_us/article/53jx5n/theres-human-hair-in-your-bread

^[2] https://en.m.wikipedia.org/wiki/Cysteine

البحر الرائق شرح كنز الدقائق ومنحة الخالق وتكملة الطوري (1/ 112) ^[3]

والأصل أن كل ما لا تحله الحياة من أجزاء الهوية محكوم بطهارته بعد موت ما هي جزؤه كالشعر والريش والمنقار والعظم والعصب والحافر والظلف واللبن والبيض الضعيف القشر والإنفحة لا خلاف بين أصحابنا في ذلك

فتح القدير للكمال ابن الهمام (1/ 96)

(قَوْلُهُ وَشَعْرُ الْمَيْتَةِ) كُلُّ مَا لَا تَحُلُّهُ الْحَيَاةُ مِنْ أَجْزَاءِ الْهُوِيَّةِ مَحْكُومٌ بِطَهَارَتِهِ بَعْدَ مَوْتِ مَا هِيَ جُزْؤُهُ كَالشَّعْرِ وَالرِّيشِ وَالْمِنْقَارِ وَالْعَظْمِ وَالْعَصَبِ وَالْحَافِرِ وَالظِّلْفِ وَاللَّبَنِ وَالْبَيْضِ الضَّعِيفِ الْقِشْرِ وَالْإِنْفَحَةِ، لَا خِلَافَ بَيْنَ أَصْحَابِنَا فِي ذَلِكَ