Is L-cysteine (E920) halal?
It depends on the source. L-cysteine (E920) is a dough conditioner that can be made from human hair, from poultry feathers, or synthetically by fermentation. SANHA lists E920 as mushbooh, meaning doubtful. Synthetic or fermented L-cysteine is halal, human hair is not, and feather-derived L-cysteine is treated differently by different scholars.
Last checked November 2, 2026. Muzzmi describes the standards and where views differ. It does not give religious rulings.
What E920 does in bread and pizza dough
L-cysteine is an amino acid. Bakeries add tiny amounts to dough because it relaxes the gluten, so the dough stretches without springing back, proves faster and runs through machines more easily. It turns up in bagels, pizza bases, commercial bread rolls, tortillas and some crackers, listed as L-cysteine, L-cysteine hydrochloride or E920.
The three sources
Human hair: historically the cheapest raw material, broken down with acid, and the reason the question goes viral. Poultry feathers: the same process applied to duck and chicken feathers, now a common source. Synthetic or fermentation: made by bacteria in a tank, with no animal input. The label never says which one was used.
What scholars and certifiers say
SANHA: mushbooh. SANHA lists E920 cysteine hydrochloride among its doubtful E-numbers because the source can be hair, feathers or synthesis, and only the synthetic and fermented forms are halal without question.
Darul Ifta New Zealand: in its halal and haram ingredients list, synthetic L-cysteine is halal, L-cysteine from human hair is not permitted, and L-cysteine from feathers is permitted only if the birds were slaughtered according to Islamic law.
Darul Iftaa Houston (Hanafi): in an answer published on IslamQA.org, L-cysteine from avian (bird) feathers is permissible, on the reasoning that feathers do not carry the ruling of flesh. Muzzmi does not rule on this: follow your own scholar.
How to check your bread
Look for a halal certification mark, which means the certifier has checked the source of every additive. Ask the brand which form of L-cysteine it uses; large bakeries usually know. If the pack only says E920 or L-cysteine with no mark, treat it as doubtful. Muzzmi's free label scanner flags E920 and other source-dependent additives on any barcode. The same question comes up for E471 and gelatin, and Halal certifiers compared explains what a mark covers.
Questions
Is there human hair in bread?
Some bread has contained L-cysteine made from human hair, which is why the question goes viral. Many makers now use feather-derived or fermented L-cysteine, and the label does not say which. A halal mark is the only sure sign of the source.
Is E920 always haram?
No. SANHA lists E920 as doubtful, not haram, because the source varies. Synthetic and fermented L-cysteine are halal. Human hair L-cysteine is not permitted, and feather-derived L-cysteine depends on the scholar you follow.
Is feather-derived L-cysteine halal?
Scholars differ. Darul Iftaa Houston says L-cysteine from bird feathers is permissible. Darul Ifta New Zealand permits it only when the birds were slaughtered according to Islamic law.
Which breads use L-cysteine?
Mostly mass-produced bread rolls, bagels, pizza bases, tortillas and crackers, where dough has to run through machines. Many supermarket loaves and most artisan breads do not use it. Check the ingredient list for L-cysteine or E920.
How can I tell the source from the label?
You cannot. The label only says L-cysteine, L-cysteine hydrochloride or E920. A halal certification mark, or a written answer from the maker, is the only way to know the source.
Sources
More guides
Is it halal? Chains and certifiers · Halal food by city · Scan a barcode