Is CYSTEINE HCL safe to use in EU cosmetics?

CYSTEINE HCL is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Always verify against the current official CosIng database before formulating.

What function does CYSTEINE HCL serve in cosmetics?

According to the EU CosIng inventory, CYSTEINE HCL carries the following function designation(s): ANTIOXIDANT, HAIR CONDITIONING, HAIR WAVING OR STRAIGHTENING, REDUCING.

What other records share CAS 52-89-1?

CAS 52-89-1 may appear across multiple EU annex records. The CAS lookup page shows all Annex II–VI entries sharing this identifier, useful for identifying cross-annex regulatory status of the same chemical substance.

How do I check if my formula contains CYSTEINE HCL?

Use the INCI Checker to screen a full ingredient list across selected markets, or use the substance market comparison to review this identity across all supported market datasets.

InventoryRef 7542315/10/2010

CYSTEINE HCL

Cysteine hydrochloride

CYSTEINE HCL is listed in the EU CosIng inventory, but no direct annex records are linked on this page yet.

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Regulatory evidence by market

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Market	Evidence status	Records	Source language
European Union	Source mapped Inventory entry; no linked annex rule	0	English and EU languages
Great Britain	Source mapped Official source mapped; ingredient rule not imported	0	English
Canada	Source mapped Official source mapped; ingredient rule not imported	0	English and French
New Zealand	Source mapped Official source mapped; ingredient rule not imported	0	English
ASEAN	Source mapped Official source mapped; ingredient rule not imported	0	English and national languages
China	Source mapped Official source mapped; ingredient rule not imported	0	Chinese with selected English material
Japan	Source mapped Official source mapped; ingredient rule not imported	0	Japanese; official English translation available
South Korea	Evidence linked Restricted Open this evidence	1	Korean with some English names
United States	Source mapped Official source mapped; ingredient rule not imported	0	English
Australia	Source mapped Official source mapped; ingredient rule not imported	0	English
Brazil	Source mapped Official source mapped; ingredient rule not imported	0	Portuguese with INCI crosswalks
India	Source mapped Official source mapped; ingredient rule not imported	0	English and Hindi
Saudi Arabia	Source mapped Official source mapped; ingredient rule not imported	0	Arabic and English

Chemical identity and properties

PubChem 2D chemical structure for CAS 52-89-1

CAS 52-89-1PubChem CID 60960

Cysteine Hydrochloride

L-cysteine hydrochloride is a hydrochloride obtained by combining L-cysteine with one molar equivalent of hydrogen chloride. It has a role as a flour treatment agent, an EC 4.3.1.3 (histidine ammonia-lyase) inhibitor and a human metabolite. It contains a L-cysteinium. — ChEBI

IUPAC name: (2R)-2-amino-3-sulfanylpropanoic acid;hydrochloride

Molecular formula: C3H8ClNO2S
Molecular weight: 157.62 g/mol
Exact mass: 156.9964274 Da
Topological polar surface area: 64.3 Å²
Hydrogen-bond donors: 4
Hydrogen-bond acceptors: 4
Covalent units: 2
Defined stereocentres: 1

Also known as

Cystein chlorideCysteine chlorhydratecysteine-hcl3-Mercaptoalanine hydrochlorideCysteine hydrochloride (anhydrous)CCRIS 3613Cysteine hydrochloride anhydrousNSC 8746

16 more reported names

EINECS 200-157-7WR 348UNII-A9U1687S1SEK 2367AI3-18781A9U1687S1SCysteine (as hydrochloride)CYSTEINE HYDROCHLORIDE, ANHYDROUSEC 200-157-7ELCYSNOURESSNSC-755898CYSTEINE HYDROCHLORIDE (II)CYSTEINE HYDROCHLORIDE ANHYDROUS (II)CYSTEINE HYDROCHLORIDE ANHYDROUS [II]CYSTEINE HYDROCHLORIDE (USP MONOGRAPH)

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:91247
ChEMBL:CHEMBL1200630
EPA DTXSID:DTXSID0020367
PubMed:9107

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Inventory details for CYSTEINE HCL

INCI name

CYSTEINE HCL

INN name

cysteine hydrochloride

Description

Cysteine hydrochloride

Record provenance

Inventory reference: 75423
Imported identity: CYSTEINE HCL
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for CYSTEINE HCL

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Key data

CAS

52-89-1

200-157-7

Restriction

—

Function

ANTIOXIDANT: Inhibiting reactions promoted by oxygen, thus avoiding oxidation and rancidity.
HAIR CONDITIONING: Enhancing the appearance and feel of hair. Leaving the hair easy to comb, supple, soft and shiny and/or imparting volume, lightness, gloss, texture, etc.
HAIR WAVING OR STRAIGHTENING: Modifying the chemical structure of the hair, allowing it to be set in the style required (permanent waves or hair straightening).
REDUCING: Changing the chemical nature of another ingredient by adding hydrogen (or removing oxygen).

Official EU ingredient-name evidence

The ingredient name exactly matches the official 2025 EU glossary of common ingredient names.

#7981 · CYSTEINE HCl

Ingredients with overlapping formulation functions

BUTYROYL GLUTATHIONEANTIMICROBIAL, ANTIOXIDANT, REDUCING

CALCIUM THIOGLYCOLATEDEPILATORY, KERATOLYTIC, REDUCING

CYSTEAMINE HCLANTIOXIDANT, HAIR WAVING OR STRAIGHTENING, REDUCING

CYSTEINEANTIOXIDANT, ANTISTATIC, FRAGRANCE, HAIR CONDITIONING, HAIR WAVING OR STRAIGHTENING, REDUCING

DIHYDROXYBENZYLIDENE SUCCINIMIDEANTIOXIDANT, BLEACHING, REDUCING, SKIN PROTECTING

DISODIUM HYDROXYSULFINOACETATEREDUCING

DISODIUM HYDROXYSULFOACETATEREDUCING

DISODIUM TETRAMETHYLHEXADECENYL SUCCINOYL CYSTEINEREDUCING, SKIN CONDITIONING, SKIN PROTECTING

Additional official and scientific sources

11 external databases to check this identity in

Each link searches that source for this identity. What each source is, and its legal weight

ECHA CHEM / Information on chemicals PubChem PUG REST EU Safety Gate cosmetic product alerts ECHA CHEM US EPA CompTox Cosmetic Ingredient Review safety assessments FDA Global Substance Registration System ILO/WHO International Chemical Safety Cards Japan NITE-CHRIP NIOSH Pocket Guide to Chemical Hazards OECD eChemPortal

How CYSTEINE HCL appears in the CosIng inventory

The CosIng inventory lists CYSTEINE HCL as a cosmetic ingredient and this page links it to 0 annex records. The inventory entry captures names and identifiers, while the annex records show where the substance is prohibited, restricted or positively listed in EU cosmetics law.

CYSTEINE HCL is also tagged with 4 cosmetic functions in the official data. Function labels describe intended use, but they do not replace regulatory review of linked annex records before formulation or labelling work.

Frequently asked questions

CYSTEINE HCL is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Absence of an annex link does not guarantee unrestricted use — always verify against the current official CosIng database before formulating.

According to the EU CosIng inventory, CYSTEINE HCL carries the following function designation(s):

CAS 52-89-1 may appear across multiple EU annex records. Viewing the CAS lookup page shows all Annex II–VI entries sharing this identifier, which is useful for identifying cross-annex regulatory status of the same chemical substance.

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Source note for CYSTEINE HCL

This page reproduces the CosIng inventory entry for CYSTEINE HCL from public European Commission cosmetic ingredient materials and shows linked identifiers even when no direct annex match is currently attached.

Use this inventory page to research CYSTEINE HCL and compare linked records, but verify restrictions and legal status against the current official source text and law before making regulatory decisions.

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Tools & next steps

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