{"id":40686,"date":"2026-07-08T11:40:00","date_gmt":"2026-07-08T11:40:00","guid":{"rendered":"https:\/\/this-is-vegan.com\/?p=40686"},"modified":"2026-07-08T14:52:54","modified_gmt":"2026-07-08T14:52:54","slug":"is-l-cysteine-vegan","status":"publish","type":"post","link":"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/","title":{"rendered":"Is L-Cysteine Vegan? Usually Not, and the Reason Is Grim"},"content":{"rendered":"<p>Here&rsquo;s a fact that puts people off their sandwich: L-cysteine, the dough conditioner labelled E920 in a lot of mass-produced bread, bagels and pizza dough, is most often made from human hair and duck feathers. So when someone asks &ldquo;is L-cysteine vegan,&rdquo; the honest answer is usually no, and the how is worse than the what.<\/p>\n<p>The good news is that a plant-based version exists, and once you know the label words to look for, avoiding the grim kind is easy.<\/p>\n<style>.tiv-verdict{border-left:6px solid #e59875;background:#f8decd;padding:18px 22px;margin:28px 0;border-radius:0 14px 14px 0;color:#0a4a4a}.tiv-verdict .tiv-badge{display:inline-block;background:#c2603a;color:#fff;padding:4px 14px;border-radius:999px;font-size:14px;font-weight:700;letter-spacing:.4px;margin-bottom:8px}.tiv-verdict p{margin:8px 0 0}.tiv-check{font-size:13px;color:#0a6b6c;margin-top:10px}details.tiv-tl{border:1px solid #e5ded4;border-radius:10px;margin:10px 0;background:#fff}details.tiv-tl summary{cursor:pointer;padding:13px 16px;font-weight:600;color:#0a4a4a}details.tiv-tl[open] summary{border-bottom:1px solid #f0ebe2}details.tiv-tl .tiv-tlb{padding:12px 16px;color:#0a4a4a}.tivq{border:2px solid #29a579;border-radius:14px;padding:22px;margin:30px 0;background:#fff}.tivq .tivq-q{margin:16px 0;padding:14px;background:#f6f3ec;border-radius:10px}.tivq .tivq-q p{font-weight:600;margin:0 0 10px}.tivq button{display:block;width:100%;text-align:left;margin:6px 0;padding:11px 14px;border:1px solid #d9d2c5;border-radius:8px;background:#fff;cursor:pointer;font-size:16px;color:#0a4a4a}.tivq button.tiv-ok{background:#29a579;color:#fff;border-color:#29a579}.tivq button.tiv-no{background:#fbe9e4;border-color:#e59875}.tivq .tivq-res{display:none;font-weight:700;margin-top:14px;font-size:18px;color:#106050}<\/style>\n<div class=\"tiv-verdict\"><span class=\"tiv-badge\">QUICK ANSWER<\/span><\/p>\n<p><strong>Usually not vegan.<\/strong> Around 90% of the world's L-cysteine (E920) is made from keratin, sourced from human hair, duck and goose feathers, or hog bristles. A plant-fermentation version made from corn or molasses exists but is a small share of the market. Only L-cysteine labelled &#8220;plant-derived,&#8221; &#8220;vegetable,&#8221; or &#8220;fermentation-based,&#8221; or a product certified vegan, is safe.<\/p>\n<p class=\"tiv-check\">Last checked: July 2026<\/p>\n<\/div>\n<figure class=\"wp-block-image size-large\" style=\"margin:26px 0;\"><img data-pin-url=\"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/\" data-pin-description=\"Assorted fresh bread and rolls from a bakery | Is L-Cysteine Vegan? Usually Not, and the Reason Is Grim\" decoding=\"async\" src=\"https:\/\/this-is-vegan.com\/wp-content\/uploads\/2026\/07\/bakery-bread-rolls-l-cysteine.jpg\" alt=\"Assorted fresh bread and rolls from a bakery\" loading=\"lazy\" style=\"width:100%;height:auto;border-radius:10px;\"\/><figcaption style=\"font-size:14px;color:#5b6b6b;text-align:center;margin-top:8px;\">Commercial bakeries use dough conditioners like L-cysteine to speed up production.<\/figcaption><\/figure>\n<h2>What L-cysteine is and where it hides<\/h2>\n<p>L-cysteine is an amino acid used as a dough conditioner. It relaxes gluten so industrial bakeries can run dough faster and get a softer crumb. You&rsquo;ll find it in a lot of commercial bread, bagels, burger buns, pizza dough and some pastries, listed as L-cysteine, cysteine, or E920.<\/p>\n<p>The problem is the source. The cheapest way to make it at scale is to extract keratin from something rich in it, then break that down into the amino acid. The keratin-rich raw materials are human hair (much of it collected in China), duck and goose feathers, and hog bristles. It is exactly as unappetising as it sounds, and it&rsquo;s why &ldquo;vegetarian&rdquo; on a label doesn&rsquo;t help you here: hair and feathers are technically slaughter-free, so a hair-derived additive can sit in a vegetarian product.<\/p>\n<h2>The plant version exists, but you have to look<\/h2>\n<p>A minority of L-cysteine (roughly 10% of supply) is made by bacterial fermentation of plant sugars from corn or molasses. It&rsquo;s molecularly identical, it&rsquo;s just more expensive, so manufacturers rarely use it unless they&rsquo;re marketing to vegans.<\/p>\n<p>That means the label is everything. Bare &ldquo;L-cysteine&rdquo; or &ldquo;E920&rdquo; should be treated as animal-derived by default. Only trust it when the maker specifies a plant source or the product carries a vegan certification.<\/p>\n<h2>How to tell, tap to expand<\/h2>\n<details class=\"tiv-tl\">\n<summary>The label just says &#8220;L-cysteine&#8221; or &#8220;E920&#8221;<\/summary>\n<div class=\"tiv-tlb\">Assume it's the keratin (hair\/feather) kind. That's the industry default. Don't buy it if you're strict.<\/div>\n<\/details>\n<details class=\"tiv-tl\">\n<summary>It says &#8220;plant-derived,&#8221; &#8220;vegetable,&#8221; or &#8220;fermentation&#8221; L-cysteine<\/summary>\n<div class=\"tiv-tlb\">This is the corn\/molasses version. Vegan-safe.<\/div>\n<\/details>\n<details class=\"tiv-tl\">\n<summary>The product is certified vegan<\/summary>\n<div class=\"tiv-tlb\">A vegan logo means the maker has confirmed a non-animal source. Safe.<\/div>\n<\/details>\n<details class=\"tiv-tl\">\n<summary>It only says &#8220;suitable for vegetarians&#8221;<\/summary>\n<div class=\"tiv-tlb\">Not good enough. Human hair and feathers are slaughter-free, so keratin-derived cysteine passes as vegetarian. Vegans should skip it.<\/div>\n<\/details>\n<figure class=\"wp-block-image size-large\" style=\"margin:26px 0;\"><img data-pin-url=\"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/\" data-pin-description=\"Fresh bagels with seasoning on a board | Is L-Cysteine Vegan? Usually Not, and the Reason Is Grim\" decoding=\"async\" src=\"https:\/\/this-is-vegan.com\/wp-content\/uploads\/2026\/07\/fresh-bagels-l-cysteine.jpg\" alt=\"Fresh bagels with seasoning on a board\" loading=\"lazy\" style=\"width:100%;height:auto;border-radius:10px;\"\/><figcaption style=\"font-size:14px;color:#5b6b6b;text-align:center;margin-top:8px;\">Bagels are one of the most common places to find L-cysteine.<\/figcaption><\/figure>\n<h2>Fact or fiction?<\/h2>\n<details class=\"tiv-tl\">\n<summary>Most L-cysteine comes from human hair. Fact or fiction?<\/summary>\n<div class=\"tiv-tlb\"><strong>Fact.<\/strong> Human hair (much of it from China) and poultry feathers are the main commercial sources.<\/div>\n<\/details>\n<details class=\"tiv-tl\">\n<summary>You mostly find it in fresh fruit and veg. Fact or fiction?<\/summary>\n<div class=\"tiv-tlb\"><strong>Fiction.<\/strong> It's a dough conditioner. Look for it in commercial bread, bagels, buns and pizza dough.<\/div>\n<\/details>\n<details class=\"tiv-tl\">\n<summary>There's a plant-based version. Fact or fiction?<\/summary>\n<div class=\"tiv-tlb\"><strong>Fact.<\/strong> Bacterial fermentation of corn or molasses makes an identical, vegan L-cysteine. It's just less common.<\/div>\n<\/details>\n<h2>Quiz: how well do you know E920?<\/h2>\n<div class=\"tivq\">\n<h3>Five questions, no cheating<\/h3>\n<div class=\"tivq-q\">\n<p>1. What is the most common source of L-cysteine?<\/p>\n<p><button data-ok>Human hair and feathers<\/button><button>Corn<\/button><button>Seaweed<\/button><\/div>\n<div class=\"tivq-q\">\n<p>2. What's L-cysteine's E-number?<\/p>\n<p><button>E471<\/button><button data-ok>E920<\/button><button>E322<\/button><\/div>\n<div class=\"tivq-q\">\n<p>3. What does it do in food?<\/p>\n<p><button data-ok>Conditions dough<\/button><button>Adds colour<\/button><button>Preserves fruit<\/button><\/div>\n<div class=\"tivq-q\">\n<p>4. Which label wording is vegan-safe?<\/p>\n<p><button data-ok>&#8220;Plant-derived&#8221; or &#8220;fermentation&#8221; L-cysteine<\/button><button>&#8220;Suitable for vegetarians&#8221;<\/button><button>Just &#8220;L-cysteine&#8221;<\/button><\/div>\n<div class=\"tivq-q\">\n<p>5. Where are you most likely to find it?<\/p>\n<p><button data-ok>Commercial bagels and bread<\/button><button>Orange juice<\/button><button>Table salt<\/button><\/div>\n<div class=\"tivq-res\"><\/div>\n<\/div>\n<p><script>document.addEventListener(\"click\",function(e){var b=e.target.closest(\".tivq button\");if(!b||b.disabled)return;var q=b.closest(\".tivq-q\"),z=b.closest(\".tivq\"),ok=b.hasAttribute(\"data-ok\");q.querySelectorAll(\"button\").forEach(function(x){x.disabled=!0;if(x.hasAttribute(\"data-ok\"))x.classList.add(\"tiv-ok\")});if(!ok)b.classList.add(\"tiv-no\");z.dataset.d=(+z.dataset.d||0)+1;z.dataset.s=(+z.dataset.s||0)+(ok?1:0);if(+z.dataset.d===z.querySelectorAll(\".tivq-q\").length){var r=z.querySelector(\".tivq-res\");r.style.display=\"block\";r.textContent=\"Your score: \"+z.dataset.s+\" of \"+z.dataset.d+\". \"+(+z.dataset.s>=4?\"You read labels like a pro.\":+z.dataset.s>=2?\"Solid. Scroll back up for the rest.\":\"Worth another read.\")}});<\/script><\/p>\n<figure class=\"wp-block-image size-large\" style=\"margin:26px 0;\"><img data-pin-url=\"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/\" data-pin-description=\"A shopper reading a product label in a supermarket | Is L-Cysteine Vegan? Usually Not, and the Reason Is Grim\" decoding=\"async\" src=\"https:\/\/this-is-vegan.com\/wp-content\/uploads\/2026\/07\/reading-food-label-l-cysteine.jpg\" alt=\"A shopper reading a product label in a supermarket\" loading=\"lazy\" style=\"width:100%;height:auto;border-radius:10px;\"\/><figcaption style=\"font-size:14px;color:#5b6b6b;text-align:center;margin-top:8px;\">Checking the label is the only way to spot plant-based L-cysteine.<\/figcaption><\/figure>\n<h2>So, is L-cysteine vegan in 2026?<\/h2>\n<p>Usually not. Treat plain L-cysteine and E920 as animal-derived unless the maker says otherwise, especially in commercial baked goods. The plant-fermented version is real and identical, so vegan bread with soft, industrial-style texture does exist. You just have to read the bag. When in doubt, freshly baked bread from a bakery that lists only flour, water, yeast and salt sidesteps the question entirely.<\/p>\n<p><strong>More vegan ingredient checks:<\/strong><\/p>\n<ul>\n<li><a href=\"https:\/\/this-is-vegan.com\/en\/are-mono-and-diglycerides-vegan\/\">Are mono and diglycerides vegan?<\/a> Another label word that could be animal<\/li>\n<li><a href=\"https:\/\/this-is-vegan.com\/en\/is-vitamin-d3-vegan\/\">Is vitamin D3 vegan?<\/a> The sheep-wool vitamin<\/li>\n<li><a href=\"https:\/\/this-is-vegan.com\/en\/is-lecithin-vegan\/\">Is lecithin vegan?<\/a> Usually fine, sometimes egg<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<div class=\"post-excerpt\">L-cysteine (E920) is a dough conditioner hiding in a lot of commercial bread and bagels. Most of it is made from human hair and duck feathers. Here&#8217;s how to spot the vegan kind.<\/div>\n<div class=\"post-more\"><a href=\"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/\" class=\"button button-primary button-effect\"><span>View Post<\/span><span><i class=\"cs-icon cs-icon-arrow-right\"><\/i><\/span><\/a><\/div>\n","protected":false},"author":5,"featured_media":40685,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"give_campaign_id":0,"_yoast_wpseo_is_cornerstone":"","_yoast_wpseo_meta-robots-noindex":"","_yoast_wpseo_meta-robots-nofollow":"","_yoast_wpseo_meta-robots-adv":"","_yoast_wpseo_bctitle":"","_yoast_wpseo_canonical":"","_yoast_wpseo_opengraph-title":"Is L-Cysteine Vegan? The Answer Is Grim","_yoast_wpseo_opengraph-description":"The dough conditioner E920 is usually made from human hair and duck feathers. Why it's not vegan and how to spot the plant-fermented version.","_yoast_wpseo_opengraph-image":"","_yoast_wpseo_opengraph-image-id":0,"_yoast_wpseo_twitter-title":"","_yoast_wpseo_twitter-description":"","_yoast_wpseo_twitter-image":"","_yoast_wpseo_twitter-image-id":0,"wprm-recipe-roundup-name":"","wprm-recipe-roundup-description":"","_yoast_wpseo_focuskeywords":"","_yoast_wpseo_keywordsynonyms":"","_outro_podcast_url":"","_yoast_wpseo_primary_category":null,"footnotes":""},"categories":[3635],"tags":[],"ernaehrungsform":[],"schwierigkeit":[],"schaerfe":[],"class_list":["post-40686","post","type-post","status-publish","format-standard","has-post-thumbnail","category-food-en"],"yoast_head":"<!-- This site is optimized with the Yoast SEO Premium plugin v27.9 (Yoast SEO v28.0) - https:\/\/yoast.com\/product\/yoast-seo-premium-wordpress\/ -->\n<title>Is L-Cysteine Vegan? Usually Not (E920 Explained)<\/title>\n<meta name=\"description\" content=\"L-cysteine (E920) is mostly made from human hair, feathers and hog bristles. Why it&#039;s usually not vegan, where it hides, and how to find plant-based L-cysteine.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/this-is-vegan.com\/en\/is-l-cysteine-vegan\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Is L-Cysteine Vegan? The Answer Is Grim\" \/>\n<meta property=\"og:description\" content=\"The dough conditioner E920 is usually made from human hair and duck feathers. 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Aus S\u00fcddeutschland, besser gesagt aus dem Schwarzwald, seit 2019 Gr\u00fcnder von This Is Vegan, mittlerweile in Bali zuhause. Von hier aus treibe ich Tierschutzprojekte voran und reise um die Welt. Vegetarier bin ich seit dem 6. Lebensjahr, vegan seit \u00fcber 20 Jahren. Mein Ansatz war nie, Leuten ein schlechtes Gewissen zu machen. Sondern zu zeigen, wie einfach, lecker und entspannt vegan im Alltag funktioniert. Anziehung statt Ablehnung. 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