{
  "$schema": "https://foodadditiveindex.com/api/v1/schema.json",
  "id": "https://foodadditiveindex.com/additives/l-cysteine-monohydrochloride",
  "slug": "l-cysteine-monohydrochloride",
  "name": "L-Cysteine monohydrochloride",
  "identifiers": {
    "e_number": null,
    "ins_number": null,
    "cas_number": "52-89-1",
    "inchikey": "IFQSXNOEEPCSLW-DKWTVANSSA-N",
    "pubchem_cid": 60960
  },
  "functional_class": null,
  "summary": "L-Cysteine monohydrochloride is the stable salt form of L-cysteine, used as a dough conditioner and a nutrient. The same source question applies to it.",
  "derivation_summary": "Made from L-cysteine, which may be produced by fermentation or by hydrolysing keratin from feathers or hair.",
  "regulatory_status": [
    {
      "jurisdiction": "US",
      "jurisdiction_name": "United States",
      "authority": "Food and Drug Administration",
      "status": "permitted",
      "status_label": "Permitted",
      "provision_count": 1,
      "provisions": [
        {
          "status": "permitted",
          "food_category": null,
          "max_level": null,
          "max_level_unit": null,
          "conditions": null,
          "effective_from": null,
          "citation": {
            "ref": "21 CFR 184.1272",
            "url": "https://www.ecfr.gov/current/title-21/section-184.1272"
          },
          "source": "ecfr",
          "retrieved_at": "2026-09-07T18:25:51.549Z"
        }
      ]
    },
    {
      "jurisdiction": "CODEX",
      "jurisdiction_name": "Codex Alimentarius",
      "authority": "Codex Alimentarius Commission / JECFA",
      "status": "not_listed",
      "status_label": "Not listed",
      "note": "Does not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.",
      "provision_count": 0,
      "provisions": []
    }
  ],
  "names": [
    {
      "name": "52-89-1",
      "type": "cas",
      "source": "pubchem"
    },
    {
      "name": "(1R)-1-carboxy-2-sulfanylethan-1-aminium chloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(2R)-2-amino-3-mercapto-propionic acid",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(2R)-2-amino-3-sulfanyl-propanoic acid;hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(2R)-2-Amino-3-sulfanylpropanoic acid hydron chloride hydrate",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(2R)-2-amino-3-sulfanylpropanoic acid;hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(R)-2-Amino-3-mercaptopropanoic acid hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(R)-2-Amino-3-mercaptopropanoicacidhydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(R)-Cysteine hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "3-Mercaptoalanine hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CAS-52-89-1",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CCRIS 3613",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cystein chloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine (as hydrochloride)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine chlorhydrate",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine HCl",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine HCl (anhydrous)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine hydrochloride (anhydrous)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE (II)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE (USP MONOGRAPH)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE ANHYDROUS (II)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE MONOHYDRATE",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE MONOHYDRATE (EP IMPURITY)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "CYSTEINE HYDROCHLORIDE MONOHYDRATE (EP MONOGRAPH)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine monohydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine, L-, hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "Cysteine, L-, monohydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "cysteine-hcl",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "cysteine-hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "ELCYS",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "H-Cys-OH inverted exclamation mark currencyHCl",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "H-Cys-OH.HCl",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-(+)-Cysteine hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-2-Amino-3-mercaptopropanoic acid monohydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "l-cysteine chlorhydrate",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-CYSTEINE HCl anhydrous",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydro-chloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride anhydrous",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride, 98.0-102.0%",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride, anhydrous, >=98% (TLC)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride, anhydrous, >=99.0% (RT)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride, anhydrous, from non-animal source, BioReagent, suitable for cell culture, >=98.0%",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine hydrochloride, Vetec(TM) reagent grade, >=98%",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine monohydrochloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine, hydrochloride (1:1)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine--hydrogen chloride (1/1)",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "l-Cysteine.HCl",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "L-cysteinium chloride",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "NOURESS",
      "type": "common",
      "source": "pubchem"
    },
    {
      "name": "(2R)-2-amino-3-sulfanylpropanoic acid hydrochloride",
      "type": "iupac",
      "source": "openfoodtox"
    },
    {
      "name": "(R)-Cysteine HCl; (R)-1-carboxy-2-mercaptoethanaminium chloride; L-(+)-Cysteine hydrochloride",
      "type": "iupac",
      "source": "pubchem"
    },
    {
      "name": "L-Cysteine monohydrochloride",
      "type": "label",
      "source": "ecfr"
    }
  ],
  "hazard_reference_values": [],
  "sources": [
    {
      "key": "ecfr",
      "name": "Electronic Code of Federal Regulations, Title 21",
      "publisher": "U.S. Government Publishing Office / National Archives",
      "licence": "Public domain",
      "url": "https://www.ecfr.gov/api/versioner/v1/full/2026-08-31/title-21.xml",
      "retrieved_at": "2026-09-07T18:25:51.549Z"
    }
  ],
  "citation_policy": "Cite as: Food Additive Index, \"L-Cysteine monohydrochloride\", https://foodadditiveindex.com/additives/l-cysteine-monohydrochloride. This site reports regulatory status and does not rate additives.",
  "generated_at": "2026-09-08T00:09:38.570Z"
}